1 Module Overview 1.1 Features 1.2 Series Comparison 2 Block Diagram 3 Pin Definitions 3.1 Pin Layout 3.2 Pin Description 4 Boot Configurations 4.1 Chip Boot Mode Control 4.2 Internal LDO (VDD_SDIO) Voltage Control 4.3 U0TXD Printing Control 4.4 Timing Control of SDIO Slave 4.5 JTAG Signal Source Control 4.6 Chip Power-up and Reset 5 Peripherals 5.1 Peripheral Overview 5.2 Digital Peripherals 5.2.1 General Purpose Input / Output Interface (GPIO) 5.2.2 Serial Peripheral Interface (SPI) 5.2.3 Universal Asynchronous Receiver Transmitter (UART) 5.2.4 I2C Interface 5.2.5 I2S Interface 5.2.6 Remote Control Peripheral 5.2.7 Pulse Counter Controller (PCNT) 5.2.8 LED PWM Controller 5.2.9 Motor Control PWM 5.2.10 SD/SDIO/MMC Host Controller 5.2.11 SDIO/SPI Slave Controller 5.2.12 TWAI Controller 5.2.13 Ethernet MAC Interface 5.3 Analog Peripherals 5.3.1 Analog-to-Digital Converter (ADC) 5.3.2 Digital-to-Analog Converter (DAC) 5.3.3 Touch Sensor 6 Electrical Characteristics 6.1 Absolute Maximum Ratings 6.2 Recommended Operating Conditions 6.3 DC Characteristics (3.3 V, 25 °C) 6.4 Current Consumption Characteristics 6.4.1 Current Consumption in Active Mode 6.4.2 Current Consumption in Other Modes 6.5 Memory Specifications 7 RF Characteristics 7.1 Wi-Fi Radio 7.1.1 Wi-Fi RF Transmitter (TX) Characteristics 7.1.2 Wi-Fi RF Receiver (RX) Characteristics 7.2 Bluetooth Radio 7.2.1 Receiver – Basic Data Rate 7.2.2 Transmitter – Basic Data Rate 7.2.3 Receiver – Enhanced Data Rate 7.2.4 Transmitter – Enhanced Data Rate 7.3 Bluetooth LE Radio 7.3.1 Receiver 7.3.2 Transmitter 8 Peripheral Schematics 9 Module Dimensions 10 PCB Layout Recommendations 10.1 PCB Land Pattern 10.2 Module Placement for PCB Design 10.3 Dimensions of RF Test Connector 11 Product Handling 11.1 Storage Conditions 11.2 Electrostatic Discharge (ESD) 11.3 Reflow Profile 11.4 Ultrasonic Vibration Datasheet Versioning Related Documentation and Resources Revision History ESP32-PICO-V3-ZERO Datasheet Version 1.6 Alexa Connect Kit (ACK) module with an Espressif chipset 2.4 GHz Wi-Fi + Bluetooth ® + Bluetooth LE support Built around ESP32 series of SiP, Xtensa ® dual-core 32-bit LX6 microprocessor 4 MB flash available On-board PCB antenna with an RF test connector ESP32-PICO-V3-ZERO www.espressif.com 1 Module Overview 1 Module Overview Note: Check the link or the QR code to make sure that you use the latest version of this document: https://espressif.com/sites/default/files/documentation/esp32-pico-v3-zero_datasheet_en.pdf 1.1 Features CPU and On-Chip Memory • ESP32 embedded, Xtensa dual-core 32-bit LX6 microprocessor, up to 240 MHz • 448 KB ROM • 520 KB SRAM • 16 KB SRAM in RTC Wi-Fi • 802.11b/g/n • Bit rate: 802.11n up to 150 Mbps • A-MPDU and A-MSDU aggregation • 0.4 µs guard interval support • Center frequency range of operating channel: 2412~2484 MHz Bluetooth • Bluetooth v4.2 BR/EDR and Bluetooth LE specification • Class-1, class-2 and class-3 transmitter • Adaptive Frequency Hopping (AFH) • CVSD and SBC for audio codec Peripherals • 2 × UART (one for connection to the host and the other for debugging), EN pin, and interrupt pin Integrated Components on Module • 40 MHz crystal oscillator • 4 MB SPI flash Antenna Options • On board PCB antenna with an RF test connector Note: This connector is for test only, and must not be used for connecting an external antenna. Operating Conditions • Operating voltage/Power supply: 3.0 ~ 3.6 V • Operating temperature range: –40 ~ 85 °C Certification • Bluetooth certification: BQB (ID: D050108) • RF certification: See Certification • Green certification: REACH/RoHS 1.2 Series Comparison ESP32-PICO-V3-ZERO is a module that is based on ESP32-PICO-V3, a System-in-Package (SiP) device. It provides complete Wi-Fi and Bluetooth functionalities with embedded Xtensa dual-core 32-bit LX6 microprocessor. The module integrates a 4 MB SPI flash. Espressif Systems 2 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 1 Module Overview Table 1: ESP32-PICO-V3-ZERO Series Comparison Ambient Temp. 1 Embedded Size 2 Ordering Code Flash (°C) Chip Revision (mm) ESP32-PICO-V3-ZERO 4 MB (Quad SPI) 3 –40 ~ 85 v3.0/v3.1 16 × 23 × 2.3 1 Ambient temperature specifies the recommended temperature range of the environment immediately outside the Espressif module. 2 For details, refer to Section 9 Module Dimensions. 3 For specifications, refer to Section 6.5 Memory Specifications. At the core of this module is the ESP32 chip, which is a single 2.4 GHz Wi-Fi and Bluetooth combo chip designed with TSMC’s 40 nm low-power technology. ESP32-PICO-V3-ZERO integrates all peripheral components seamlessly, including a crystal oscillator, flash, filter capacitors and RF matching links in one single package. Module assembly and testing are already done at SiP level. As such, ESP32-PICO-V3-ZERO reduces the complexity of supply chain and improves control efficiency. It is ultra-small in size, with robust performance and low energy consumption. ESP32-PICO-V3-ZERO is a module for Alexa Connect Kit (ACK), a managed service that makes it easy to integrate Alexa into your products. With ESP32-PICO-V3-ZERO and its default firmware, you can connect your devices or system to Alexa and the Internet without worrying about managing cloud services, writing an Alexa Skill, or developing complex networking and security firmware. If you add ESP32-PICO-V3-ZERO to your device, you can easily, quickly and economically create products that customers love. Note: • For more information on ESP32, please refer to ESP32 Series Datasheet. • For more information on ESP32-PICO-V3, please refer to ESP32-PICO Series Datasheet. Espressif Systems 3 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 Contents Contents 1 Module Overview 2 1.1 Features 2 1.2 Series Comparison 2 2 Block Diagram 8 3 Pin Definitions 9 3.1 Pin Layout 9 3.2 Pin Description 9 4 Boot Configurations 11 4.1 Chip Boot Mode Control 12 4.2 Internal LDO (VDD_SDIO) Voltage Control 13 4.3 U0TXD Printing Control 14 4.4 Timing Control of SDIO Slave 14 4.5 JTAG Signal Source Control 14 4.6 Chip Power-up and Reset 14 5 Peripherals 16 5.1 Peripheral Overview 16 5.2 Digital Peripherals 16 5.2.1 General Purpose Input / Output Interface (GPIO) 16 5.2.2 Serial Peripheral Interface (SPI) 16 5.2.3 Universal Asynchronous Receiver Transmitter (UART) 17 5.2.4 I2C Interface 17 5.2.5 I2S Interface 18 5.2.6 Remote Control Peripheral 18 5.2.7 Pulse Counter Controller (PCNT) 19 5.2.8 LED PWM Controller 19 5.2.9 Motor Control PWM 20 5.2.10 SD/SDIO/MMC Host Controller 21 5.2.11 SDIO/SPI Slave Controller 21 5.2.12 TWAI ® Controller 22 5.2.13 Ethernet MAC Interface 22 5.3 Analog Peripherals 23 5.3.1 Analog-to-Digital Converter (ADC) 23 5.3.2 Digital-to-Analog Converter (DAC) 24 5.3.3 Touch Sensor 24 6 Electrical Characteristics 26 6.1 Absolute Maximum Ratings 26 6.2 Recommended Operating Conditions 26 6.3 DC Characteristics (3.3 V, 25 °C) 26 Espressif Systems 4 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 Contents 6.4 Current Consumption Characteristics 27 6.4.1 Current Consumption in Active Mode 27 6.4.2 Current Consumption in Other Modes 28 6.5 Memory Specifications 28 7 RF Characteristics 30 7.1 Wi-Fi Radio 30 7.1.1 Wi-Fi RF Transmitter (TX) Characteristics 30 7.1.2 Wi-Fi RF Receiver (RX) Characteristics 31 7.2 Bluetooth Radio 32 7.2.1 Receiver – Basic Data Rate 32 7.2.2 Transmitter – Basic Data Rate 33 7.2.3 Receiver – Enhanced Data Rate 33 7.2.4 Transmitter – Enhanced Data Rate 34 7.3 Bluetooth LE Radio 35 7.3.1 Receiver 35 7.3.2 Transmitter 35 8 Peripheral Schematics 36 9 Module Dimensions 38 10 PCB Layout Recommendations 39 10.1 PCB Land Pattern 39 10.2 Module Placement for PCB Design 40 10.3 Dimensions of RF Test Connector 42 11 Product Handling 43 11.1 Storage Conditions 43 11.2 Electrostatic Discharge (ESD) 43 11.3 Reflow Profile 43 11.4 Ultrasonic Vibration 44 Datasheet Versioning 45 Related Documentation and Resources 46 Revision History 47 Espressif Systems 5 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 List of Tables List of Tables 1 ESP32-PICO-V3-ZERO Series Comparison 3 2 Pin Definitions 10 3 Default Configuration of Strapping Pins 11 4 Description of Timing Parameters for the Strapping Pins 12 5 Chip Boot Mode Control 12 6 U0TXD Printing Control 14 7 Timing Control of SDIO Slave 14 8 Description of Timing Parameters for Power-up and Reset 15 9 ADC Characteristics 23 10 ADC Calibration Results 24 11 Capacitive-Sensing GPIOs Available on ESP32 24 12 Absolute Maximum Ratings 26 13 Recommended Operating Conditions 26 14 DC Characteristics (3.3 V, 25 °C) 26 15 Current Consumption for Wi-Fi (2.4 GHz) in Active Mode 27 16 Current Consumption Depending on Work Modes 28 17 Flash Specifications 28 18 Wi-Fi RF Characteristics 30 19 TX Power with Spectral Mask and EVM Meeting 802.11 Standards 30 20 TX EVM Test 1 30 21 RX Sensitivity 31 22 Maximum RX Level 32 23 RX Adjacent Channel Rejection 32 24 Bluetooth LE RF Characteristics 32 25 Receiver Characteristics – Basic Data Rate 33 26 Transmitter Characteristics – Basic Data Rate 33 27 Receiver Characteristics – Enhanced Data Rate 34 28 Transmitter Characteristics – Enhanced Data Rate 34 29 Receiver Characteristics – Bluetooth LE 35 30 Transmitter Characteristics – Bluetooth LE 35 Espressif Systems 6 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 List of Figures List of Figures 1 ESP32-PICO-V3-ZERO Block Diagram 8 2 Pin Layout (Top View) 9 3 Visualization of Timing Parameters for the Strapping Pins 12 4 Chip Boot Flow 13 5 Visualization of Timing Parameters for Power-up and Reset 14 6 Peripheral Schematics 36 7 Physical Dimensions 38 8 Recommended PCB Land Pattern 39 9 Module Placement on a Base Board 40 10 Keepout Zone for Module’s Antenna on the Base Board 41 11 Dimensions of RF Test Connector 42 12 Reflow Profile 43 Espressif Systems 7 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 2 Block Diagram 2 Block Diagram Figure 1: ESP32-PICO-V3-ZERO Block Diagram Note: For the pin mapping between the chip and the in-package flash/PSRAM, please refer to ESP32 Series Datasheet > Table Pin Mapping Between Chip and In-package Flash/PSRAM. Espressif Systems 8 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 3 Pin Definitions 3 Pin Definitions 3.1 Pin Layout The pin diagram below shows the approximate location of pins on the module. For the actual diagram drawn to scale, please refer to Figure 9 Module Dimensions. Pin 1 Pin 2 Pin 3 Pin 4 Pin 5 Pin 6 Pin 7 Pin 8 Pin 9 Pin 10 Pin 11 Pin 12 Pin 13 Pin 14 Pin 15 Pin 16 Pin 48 Pin 47 Pin 46 Pin 45 Pin 44 Pin 43 Pin 42 Pin 41 Pin 40 Pin 39 Pin 38 Pin 37 Pin 36 Pin 35 Pin 34 Pin 33 Pin 64 Pin 63 Pin 62 Pin 61 Pin 60 Pin 59 Pin 58 Pin 57 Pin 56 Pin 55 Pin 54 Pin 53 Pin 52 Pin 51 Pin 50 Pin 49 Pin 17 Pin 18 Pin 19 Pin 20 Pin 21 Pin 22 Pin 23 Pin 25 Pin 26 Pin 27 Pin 28 Pin 29 Pin 30 Pin 32 Pin 66 GND Pin 67 GND Pin 65 GND Pin 68 GND Pin 75 GND Pin 72 GND Pin 69 GND Pin 70 GND Pin 71 GND Pin 73 GND Pin 74 GND Pin 77 GND Pin 76 GND NC NC DBG_RXD/IO3 DBG_TXD/IO1 NC NC NC NC NC NC NC GND NC NC NC NC NC NC EN VDD33 GND NC INT_B/IO27 NC U1RXD/IO22 GND VDD33 GND U1TXD/IO19 NC NC NC GND NC NC NC NC GND Pin 31 Pin 24 GND GND GND GND GND GND GND GND GND GND GND GND GND GND GND GND GND GND GND GND GND GND GND GND GND GND Antenna area A Figure 2: Pin Layout (Top View) Note A: The zone marked with dotted lines is the antenna keepout zone. 3.2 Pin Description The module has 77 pins. See pin definitions in Table 2. Espressif Systems 9 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 3 Pin Definitions For peripheral pin configurations, please refer to ESP32 Series Datasheet. Table 2: Pin Definitions Name No. Type 1 Function NC 1, 2, 5 ~ 11, 13 ~ 18, 33 ~ 36, 38 ~ 40, 46, 48 NA Do not connect. These pins must be left floating. DBG_RXD/IO3 3 I GPIO3, Debugging UART RX, GPIO3 DBG_TXD/IO1 4 O GPIO1, Debugging UART TX, GPIO1 EN 19 I High: On; enables the module Low: Off; the module powers off Note: Do not leave this pin floating. VDD33 22 P Power supply (3.0 V ~ 3.6 V) U1TXD/IO19 41 O UART TX, connected to host RX, GPIO19 VDD33 43 P Power supply (3.0 V ~ 3.6 V) U1RXD/IO22 45 I UART RX, connected to host TX, GPIO22 INT_B/IO27 47 O Host interrupt, connected to host GPIO, GPIO27 GND 12, 20, 21, 23 ~ 32, 37, 42, 44, 49 ~ 77 P Ground 1 P: power supply; I: input; O: output. Espressif Systems 10 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 4 Boot Configurations 4 Boot Configurations Note: The content below is excerpted from ESP32 Series Datasheet > Section Boot Configurations. The chip allows for configuring the following boot parameters through strapping pins and eFuse bits at power-up or a hardware reset, without microcontroller interaction. • Chip boot mode – Strapping pin: GPIO0 and GPIO2 • Internal LDO (VDD_SDIO) Voltage – Strapping pin: MTDI – eFuse bit: EFUSE_SDIO_FORCE and EFUSE_SDIO_TIEH • U0TXD printing – Strapping pin: MTDO • Timing of SDIO Slave – Strapping pin: MTDO and GPIO5 • JTAG signal source – eFuse bit: EFUSE_DISABLE_JTAG The default values of all the above eFuse bits are 0, which means that they are not burnt. Given that eFuse is one-time programmable, once an eFuse bit is programmed to 1, it can never be reverted to 0. For how to program eFuse bits, please refer to ESP32 Technical Reference Manual > Chapter eFuse Controller. The default values of the strapping pins, namely the logic levels, are determined by pins’ internal weak pull-up/pull-down resistors at reset if the pins are not connected to any circuit, or connected to an external high-impedance circuit. Table 3: Default Configuration of Strapping Pins Strapping Pin Default Configuration Bit Value GPIO0 Pull-up 1 GPIO2 Pull-down 0 MTDI Pull-down 0 MTDO Pull-up 1 GPIO5 Pull-up 1 To change the bit values, the strapping pins should be connected to external pull-down/pull-up resistances. If the ESP32 is used as a device by a host MCU, the strapping pin voltage levels can also be controlled by the host MCU. All strapping pins have latches. At system reset, the latches sample the bit values of their respective strapping pins and store them until the chip is powered down or shut down. The states of latches cannot be changed in Espressif Systems 11 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 4 Boot Configurations any other way. It makes the strapping pin values available during the entire chip operation, and the pins are freed up to be used as regular IO pins after reset. The timing of signals connected to the strapping pins should adhere to the setup time and hold time specifications in Table 4 and Figure 3. Table 4: Description of Timing Parameters for the Strapping Pins Parameter Description Min (ms) t SU Setup time is the time reserved for the power rails to stabilize before the CHIP_PU pin is pulled high to activate the chip. 0 t H Hold time is the time reserved for the chip to read the strapping pin values after CHIP_PU is already high and before these pins start operating as regular IO pins. 1 Strapping pin V IH_nRST V IH t SU t H CHIP_PU Figure 3: Visualization of Timing Parameters for the Strapping Pins 4.1 Chip Boot Mode Control GPIO0 and GPIO2 control the boot mode after the reset is released. See Table 5 Chip Boot Mode Control. Table 5: Chip Boot Mode Control Boot Mode GPIO0 GPIO2 SPI Boot Mode 1 Any value Joint Download Boot Mode 2 0 0 1 Bold marks the default value and configuration. 2 Joint Download Boot mode supports the following download methods: • SDIO Download Boot • UART Download Boot In Joint Download Boot mode, the detailed boot flow of the chip is put below 4. Espressif Systems 12 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 4 Boot Configurations Figure 4: Chip Boot Flow uart_download_dis controls boot mode behaviors: It permanently disables Download Boot mode when uart_download_dis is set to 1 (valid only for ESP32 chip revisions v3.0 and higher). 4.2 Internal LDO (VDD_SDIO) Voltage Control MTDI is used to select the VDD_SDIO power supply voltage at reset: • MTDI = 0 (by default), VDD_SDIO pin is powered directly from VDD3P3_RTC. Typically this voltage is 3.3 V. For more information, see ESP32 Series Datasheet > Section Power Scheme. • MTDI = 1, VDD_SDIO pin is powered from internal 1.8 V LDO. This functionality can be overridden by setting EFUSE_SDIO_FORCE to 1, in which case the EFUSE_SDIO_TIEH determines the VDD_SDIO voltage: • EFUSE_SDIO_TIEH = 0, VDD_SDIO connects to 1.8 V LDO. • EFUSE_SPI_TIEH = 1, VDD_SDIO connects to VDD3P3_RTC. Espressif Systems 13 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 4 Boot Configurations 4.3 U0TXD Printing Control During booting, the strapping pin MTDO can be used to control the U0TXD Printing, as Table 6 shows. Table 6: U0TXD Printing Control U0TXD Printing Control MTDO Enabled 1 1 Disabled 0 1 Bold marks the default value and configuration. 4.4 Timing Control of SDIO Slave The strapping pin MTDO and GPIO5 can be used to control the timing of SDIO slave, see Table 7 Timing Control of SDIO Slave. Table 7: Timing Control of SDIO Slave Edge behavior MTDO GPIO5 Falling edge sampling, falling edge output 0 0 Falling edge sampling, rising edge output 0 1 Rising edge sampling, falling edge output 1 0 Rising edge sampling, rising edge output 1 1 1 Bold marks the default value and configuration. 4.5 JTAG Signal Source Control If EFUSE_DISABLE_JTAG is set to 1, the source of JTAG signals can be disabled. 4.6 Chip Power-up and Reset Once the power is supplied to the chip, its power rails need a short time to stabilize. After that, CHIP_PU – the pin used for power-up and reset – is pulled high to activate the chip. For information on CHIP_PU as well as power-up and reset timing, see Figure 5 and Table 8. V IL_nRST t ST BL t RST VDD3P3_RTC Min VDD CHIP_PU Figure 5: Visualization of Timing Parameters for Power-up and Reset Espressif Systems 14 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 4 Boot Configurations Table 8: Description of Timing Parameters for Power-up and Reset Parameter Description Min (µs) t ST BL Time reserved for the 3.3 V rails to stabilize before the CHIP_PU pin is pulled high to activate the chip 50 t RST Time reserved for CHIP_PU to stay below V IL_nRST to reset the chip (see Table 14) 50 For details, please refer to ESP32 Series Datasheet > Section Chip Power-up and Reset. Espressif Systems 15 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 5 Peripherals 5 Peripherals 5.1 Peripheral Overview ESP32 chip integrates a rich set of peripherals including SPI, I2S, UART, I2C, LED PWM, TWAI ® , ADC, DAC, touch sensor, etc. Note: • The content below is sourced from ESP32 Series Datasheet > Section Functional Description. Some information may not be applicable to ESP32-PICO-V3-ZERO as not all the IO signals are exposed on the module. • To learn more about peripheral signals, please refer to ESP32 Technical Reference Manual > Section Peripheral Signal List. 5.2 Digital Peripherals 5.2.1 General Purpose Input / Output Interface (GPIO) ESP32 has 34 GPIO pins which can be assigned various functions by programming the appropriate registers. There are several kinds of GPIOs: digital-only, analog-enabled, capacitive-touch-enabled, etc. Analog-enabled GPIOs and Capacitive-touch-enabled GPIOs can be configured as digital GPIOs. Most of the digital GPIOs can be configured as internal pull-up or pull-down, or set to high impedance. When configured as an input, the input value can be read through the register. The input can also be set to edge-trigger or level-trigger to generate CPU interrupts. Most of the digital IO pins are bi-directional, non-inverting and tristate, including input and output buffers with tristate control. These pins can be multiplexed with other functions, such as the SDIO, UART, SPI, etc. (More details can be found in ESP32 Series Datasheet > Appendix, Table IO_MUX. ) For low-power operations, the GPIOs can be set to hold their states. 5.2.2 Serial Peripheral Interface (SPI) ESP32 integrates four SPI controllers which can be used to communicate with external devices that use the SPI protocol. Controller SPI0 is used as a buffer for accessing external memory. Controller SPI1 can be used as a master. Controllers SPI2 and SPI3 can be configured as either a master or a slave. SPI1, SPI2, and SPI3 use signal buses prefixed with SPI, HSPI, and VSPI, respectively. Features of General Purpose SPI (GP-SPI) • Programmable data transfer length, in multiples of 1 byte • Four-line full-duplex/half-duplex communication and three-line half-duplex communication support • Master mode and slave mode • Programmable CPOL and CPHA • Programmable clock Espressif Systems 16 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 5 Peripherals Pin Assignment For SPI, the pins are multiplexed with GPIO6 ~ GPIO11 via the IO MUX. For HSPI, the pins are multiplexed with GPIO2, GPIO4, GPIO12 ~ GPIO15 via the IO MUX. For VSPI, the pins are multiplexed with GPIO5, GPIO18 ~ GPIO19, GPIO21 ~ GPIO23 via the IO MUX. For more information about the pin assignment, see ESP32 Series Datasheet > Section Peripheral Pin Configurations and ESP32 Technical Reference Manual > Chapter IO_MUX and GPIO Matrix. 5.2.3 Universal Asynchronous Receiver Transmitter (UART) The UART in the ESP32 chip facilitates the transmission and reception of asynchronous serial data between the chip and external UART devices. It consists of two UARTs in the main system, and one low-power LP UART. Feature List • Programmable baud rates up to 5 MBaud • RAM shared by TX FIFOs and RX FIFOs • Supports input baud rate self-check • Support for various lengths of data bits and stop bits • Parity bit support • Asynchronous communication (RS232 and RS485) and IrDA support • Supports DMA to communicate data in high speed • Supports UART wake-up • Supports both software and hardware flow control Pin Assignment The pins for UART can be chosen from any GPIOs via the GPIO Matrix. For more information about the pin assignment, see ESP32 Series Datasheet > Section Peripheral Pin Configurations and ESP32 Technical Reference Manual > Chapter IO_MUX and GPIO Matrix. 5.2.4 I2C Interface ESP32 has two I2C bus interfaces which can serve as I2C master or slave, depending on the user’s configuration. Feature List • Two I2C controllers: one in the main system and one in the low-power system • Standard mode (100 Kbit/s) • Fast mode (400 Kbit/s) • Up to 5 MHz, yet constrained by SDA pull-up strength Espressif Systems 17 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 5 Peripherals • Support for 7-bit and 10-bit addressing, as well as dual address mode • Supports continuous data transmission with disabled Serial Clock Line (SCL) • Supports programmable digital noise filter Users can program command registers to control I2C interfaces, so that they have more flexibility. Pin Assignment For regular I2C, the pins used can be chosen from any GPIOs via the GPIO Matrix. For more information about the pin assignment, see ESP32 Series Datasheet > Section Peripheral Pin Configurations and ESP32 Technical Reference Manual > Chapter IO_MUX and GPIO Matrix. 5.2.5 I2S Interface The I2S Controller in the ESP32 chip provides a flexible communication interface for streaming digital data in multimedia applications, particularly digital audio applications. Feature List • Master mode and slave mode • Full-duplex and half-duplex communications • A variety of audio standards supported • Configurable high-precision output clock • Supports PDM signal input and output • Configurable data transmit and receive modes Pin Assignment The pins for the I2S Controller can be chosen from any GPIOs via the GPIO Matrix. For more information about the pin assignment, see ESP32 Series Datasheet > Section Peripheral Pin Configurations and ESP32 Technical Reference Manual > Chapter IO_MUX and GPIO Matrix. 5.2.6 Remote Control Peripheral The Remote Control Peripheral (RMT) controls the transmission and reception of infrared remote control signals. Feature List • Eight channels for sending and receiving infrared remote control signals • Independent transmission and reception capabilities for each channel • Clock divider counter, state machine, and receiver for each RX channel • Supports various infrared protocols Espressif Systems 18 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 5 Peripherals Pin Assignment The pins for the Remote Control Peripheral can be chosen from any GPIOs via the GPIO Matrix. For more information about the pin assignment, see ESP32 Series Datasheet > Section Peripheral Pin Configurations and ESP32 Technical Reference Manual > Chapter IO_MUX and GPIO Matrix. 5.2.7 Pulse Counter Controller (PCNT) The pulse counter controller (PCNT) is designed to count input pulses by tracking rising and falling edges of the input pulse signal. Feature List • Eight independent pulse counter units • Each pulse counter unit has a 16-bit signed counter register and two channels • Counter modes: increment, decrement, or disable • Glitch filtering for input pulse signals and control signals • Selection between counting on rising or falling edges of the input pulse signal Pin Assignment The pins for the Pulse Count Controller can be chosen from any GPIOs via the GPIO Matrix. For more information about the pin assignment, see ESP32 Series Datasheet > Section Peripheral Pin Configurations and ESP32 Technical Reference Manual > Chapter IO_MUX and GPIO Matrix. 5.2.8 LED PWM Controller The LED PWM Controller (LEDC) is designed to generate PWM signals for LED control. Feature List • Sixteen independent PWM generators • Maximum PWM duty cycle resolution of 20 bits • Eight independent timers with 20-bit counters, configurable fractional clock dividers and counter overflow values • Adjustable phase of PWM signal output • PWM duty cycle dithering • Automatic duty cycle fading Pin Assignment The pins for the LED PWM Controller can be chosen from any GPIOs via the GPIO Matrix. For more information about the pin assignment, see ESP32 Series Datasheet > Section Peripheral Pin Configurations and ESP32 Technical Reference Manual > Chapter IO_MUX and GPIO Matrix. Espressif Systems 19 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 5 Peripherals 5.2.9 Motor Control PWM The Pulse Width Modulation (PWM) controller can be used for driving digital motors and smart lights. The controller consists of PWM timers, the PWM operator and a dedicated capture sub-module. Each timer provides timing in synchronous or independent form, and each PWM operator generates a waveform for one PWM channel. The dedicated capture sub-module can accurately capture events with external timing. Feature List • Three PWM timers for precise timing and frequency control – Every PWM timer has a dedicated 8-bit clock prescaler – The 16-bit counter in the PWM timer can work in count-up mode, count-down mode, or count-up-down mode – A hardware sync can trigger a reload on the PWM timer with a phase register. It will also trigger the prescaler’ restart, so that the timer’s clock can also be synced, with selectable hardware synchronization source • Three PWM operators for generating waveform pairs – Six PWM outputs to operate in several topologies – Configurable dead time on rising and falling edges; each set up independently – Modulating of PWM output by high-frequency carrier signals, useful when gate drivers are insulated with a transformer • Fault Detection module – Programmable fault handling in both cycle-by-cycle mode and one-shot mode – A fault condition can force the PWM output to either high or low logic levels • Capture module for hardware-based signal processing – Speed measurement of rotating machinery – Measurement of elapsed time between position sensor pulses – Period and duty cycle measurement of pulse train signals – Decoding current or voltage amplitude derived from duty-cycle-encoded signals of current/voltage sensors – Three individual capture channels, each of which with a 32-bit time-stamp register – Selection of edge polarity and prescaling of input capture signals – The capture timer can sync with a PWM timer or external signals Pin Assignment The pins for the Motor Control PWM can be chosen from any GPIOs via the GPIO Matrix. For more information about the pin assignment, see ESP32 Series Datasheet > Section Peripheral Pin Configurations and ESP32 Technical Reference Manual > Chapter IO_MUX and GPIO Matrix. Espressif Systems 20 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 5 Peripherals 5.2.10 SD/SDIO/MMC Host Controller An SD/SDIO/MMC host controller is available on ESP32. Feature List • Supports two external cards • Supports SD Memory Card standard: version 3.0 and version 3.01) • Supports SDIO Version 3.0 • Supports Consumer Electronics Advanced Transport Architecture (CE-ATA Version 1.1) • Supports Multimedia Cards (MMC version 4.41, eMMC version 4.5 and version 4.51) The controller allows up to 80 MHz clock output in three different data-bus modes: 1-bit, 4-bit, and 8-bit modes. It supports two SD/SDIO/MMC4.41 cards in a 4-bit data-bus mode. It also supports one SD card operating at 1.8 V. Pin Assignment The pins for SD/SDIO/MMC Host Controller are multiplexed with GPIO2, GPIO4, GPIO6 ~ GPIO15 via IO MUX. For more information about the pin assignment, see ESP32 Series Datasheet > Section Peripheral Pin Configurations and ESP32 Technical Reference Manual > Chapter IO_MUX and GPIO Matrix. 5.2.11 SDIO/SPI Slave Controller ESP32 integrates an SD device interface that conforms to the industry-standard SDIO Card Specification Version 2.0, and allows a host controller to access the SoC, using the SDIO bus interface and protocol. ESP32 acts as the slave on the SDIO bus. The host can access the SDIO-interface registers directly and can access shared memory via a DMA engine, thus maximizing performance without engaging the processor cores. Feature List The SDIO/SPI slave controller supports the following features: • SPI, 1-bit SDIO, and 4-bit SDIO transfer modes over the full clock range from 0 to 50 MHz • Configurable sampling and driving clock edge • Special registers for direct access by host • Interrupts to host for initiating data transfer • Automatic loading of SDIO bus data and automatic discarding of padding data • Block size of up to 512 bytes • Interrupt vectors between the host and the slave, allowing both to interrupt each other • Supports DMA for data transfer Espressif Systems 21 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 5 Peripherals Pin Assignment The pins for SDIO/SPI Slave Controller are multiplexed with GPIO2, GPIO4, GPIO6 ~ GPIO15 via IO MUX. For more information about the pin assignment, see ESP32 Series Datasheet > Section Peripheral Pin Configurations and ESP32 Technical Reference Manual > Chapter IO_MUX and GPIO Matrix. 5.2.12 TWAI ® Controller The Two-wire Automotive Interface (TWAI ® ) is a multi-master, multi-cast communication protocol designed for automotive applications. The TWAI controller facilitates the communication based on this protocol. Feature List • Compatible with ISO 11898-1 protocol (CAN Specification 2.0) • Standard frame format (11-bit ID) and extended frame format (29-bit ID) • Bit rates: – From 25 Kbit/s to 1 Mbit/s in chip revision v0.0/v1.0/v1.1 – From 12.5 Kbit/s to 1 Mbit/s in chip revision v3.0/v3.1 • Multiple modes of operation: Normal, Listen Only, and Self-Test • 64-byte receive FIFO • Special transmissions: single-shot transmissions and self reception • Acceptance filter (single and dual filter modes) • Error detection and handling: error counters, configurable error interrupt threshold, error code capture, arbitration lost capture Pin Assignment The pins for the Two-wire Automotive Interface can be chosen from any GPIOs via the GPIO Matrix. For more information about the pin assignment, see ESP32 Series Datasheet > Section Peripheral Pin Configurations and ESP32 Technical Reference Manual > Chapter IO_MUX and GPIO Matrix. 5.2.13 Ethernet MAC Interface An IEEE-802.3-2008-compliant Media Access Controller (MAC) is provided for Ethernet LAN communications. ESP32 requires an external physical interface device (PHY) to connect to the physical LAN bus (twisted-pair, fiber, etc.). The PHY is connected to ESP32 through 17 signals of MII or nine signals of RMII. Feature List • 10 Mbps and 100 Mbps rates • Dedicated DMA controller allowing high-speed transfer between the dedicated SRAM and Ethernet MAC • Tagged MAC frame (VLAN support) • Half-duplex (CSMA/CD) and full-duplex operation Espressif Systems 22 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 5 Peripherals • MAC control sublayer (control frames) • 32-bit CRC generation and removal • Several address-filtering modes for physical and multicast address (multicast and group addresses) • 32-bit status code for each transmitted or received frame • Internal FIFOs to buffer transmit and receive frames. The transmit FIFO and the receive FIFO are both 512 words (32-bit) • Hardware PTP (Precision Time Protocol) in accordance with IEEE 1588 2008 (PTP V2) • 25 MHz/50 MHz clock output Pin Assignment For information about the pin assignment of Ethernet MAC Interface, see ESP32 Series Datasheet > Section Peripheral Pin Configurations and ESP32 Technical Reference Manual > Chapter IO_MUX and GPIO Matrix. 5.3 Analog Peripherals 5.3.1 Analog-to-Digital Converter (ADC) ESP32 integrates two 12-bit SAR ADCs and supports measurements on 18 channels (analog-enabled pins). The ULP coprocessor in ESP32 is also designed to measure voltage, while operating in the sleep mode, which enables low-power consumption. The CPU can be woken up by a threshold setting and/or via other triggers. Table 9 describes the ADC characteristics. Table 9: ADC Characteristics Parameter Description Min Max Unit DNL (Differential nonlinearity) RTC controller; ADC connected to an –7 7 LSB external 100 nF capacitor; DC signal input; INL (Integral nonlinearity) ambient temperature at 25 °C; –12 12 LSB Wi-Fi&Bluetooth off Sampling rate RTC controller — 200 ksps DIG controller — 2 Msps Notes: • When atten = 3 and the measurement result is above 3000 (voltage at approx. 2450 mV), the ADC accuracy will be worse than described in the table above. • To get better DNL results, users can take multiple sampling tests with a filter, or calculate the average value. • The input voltage range of GPIO pins within VDD3P3_RTC domain should strictly follow the DC characteristics provided in Table 14. Otherwise, measurement errors may be introduced, and chip performance may be affected. By default, there are ±6% differences in measured results between chips. ESP-IDF provides couple of calibration methods for ADC1. Results after calibration using eFuse Vref value are shown in Table 10. For higher accuracy, users may apply other calibration methods provided in ESP-IDF, or implement their own. Espressif Systems 23 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 5 Peripherals Table 10: ADC Calibration Results Parameter Description Min Max Unit Total error Atten = 0, effective measurement range of 100 ∼ 950 mV –23 23 mV Atten = 1, effective measurement range of 100 ∼ 1250 mV –30 30 mV Atten = 2, effective measurement range of 150 ∼ 1750 mV –40 40 mV Atten = 3, effective measurement range of 150 ∼ 2450 mV –60 60 mV Pin Assignment With appropriate settings, the ADCs can be configured to measure voltage on 18 pins maximum. For detailed information about the pin assignment, see ESP32 Series Datasheet > Section Peripheral Pin Configurations and ESP32 Technical Reference Manual > Chapter IO_MUX and GPIO Matrix. 5.3.2 Digital-to-Analog Converter (DAC) Two 8-bit DAC channels can be used to convert two digital signals into two analog voltage signal outputs. The design structure is composed of integrated resistor strings and a buffer. This dual DAC supports power supply as input voltage reference. The two DAC channels can also support independent conversions. Pin Assignment The DAC can be configured by GPIO 25 and GPIO 26. For detailed information about the pin assignment, see ESP32 Series Datasheet > Section Peripheral Pin Configurations and ESP32 Technical Reference Manual > Chapter IO_MUX and GPIO Matrix. 5.3.3 Touch Sensor ESP32 has 10 capacitive-sensing GPIOs, which detect variations induced by touching or approaching the GPIOs with a finger or other objects. The low-noise nature of the design and the high sensitivity of the circuit allow relatively small pads to be used. Arrays of pads can also be used, so that a larger area or more points can be detected. Pin Assignment The 10 capacitive-sensing GPIOs are listed in Table 11. Table 11: Capacitive-Sensing GPIOs Available on ESP32 Capacitive-Sensing Signal Name Pin Name T0 GPIO4 T1 GPIO0 T2 GPIO2 T3 MTDO T4 MTCK T5 MTDI T6 MTMS T7 GPIO27 T8 32K_XN Espressif Systems 24 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 5 Peripherals Capacitive-Sensing Signal Name Pin Name T9 32K_XP Note: ESP32 Touch Sensor has not passed the Conducted Susceptibility (CS) test for now, and thus has limited application scenarios. Espressif Systems 25 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 6 Electrical Characteristics 6 Electrical Characteristics 6.1 Absolute Maximum Ratings Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only and functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. Table 12: Absolute Maximum Ratings Symbol Parameter Min Max Unit VDD33 Power supply voltage –0.3 3.6 V T ST ORE Storage temperature –40 85 °C * Please see Appendix IO MUX of ESP32 Series Datasheet for IO’s power domain. 6.2 Recommended Operating Conditions Table 13: Recommended Operating Conditions Symbol Parameter Min Typ Max Unit VDD33 Power supply voltage 3.0 3.3 3.6 V I V DD Current delivered by external power supply 0.5 — — A T A Operating ambient temperature –40 — 85 °C 6.3 DC Characteristics (3.3 V, 25 °C) Table 14: DC Characteristics (3.3 V, 25 °C) Symbol Parameter Min Typ Max Unit C IN Pin capacitance — 2 — pF V IH High-level input voltage 0.75 × VDD 1 — VDD 1 + 0.3 V V IL Low-level input voltage –0.3 — 0.25 × VDD 1 V I IH High-level input current — — 50 nA I IL Low-level input current — — 50 nA V OH High-level output voltage 0.8 × VDD 1 — — V V OL Low-level output voltage — — 0.1 × VDD 1 V Cont’d on next page Espressif Systems 26 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 6 Electrical Characteristics Table 14 – cont’d from previous page Symbol Parameter Min Typ Max Unit I OH High-level source current (VDD 1 = 3.3 V, V OH >= 2.64 V, output drive strength set to the maximum) VDD3P3_CPU power domain 1, 2 — 40 — mA VDD3P3_RTC power domain 1, 2 — 40 — mA VDD_SDIO power domain 1, 3 — 20 — mA I OL Low-level sink current (VDD 1 = 3.3 V, V OL = 0.495 V, output drive strength set to the maximum) — 28 — mA R P U Resistance of internal pull-up resistor — 45 — kΩ R P D Resistance of internal pull-down resistor — 45 — kΩ V IH_nRST Chip reset release voltage (CHIP_PU voltage is within the specified range) 0.75 × VDD 1 — VDD 1 + 0.3 V V IL_nRST Low-level input voltage of CHIP_PU to shut down the chip — — 0.6 V 1 Please see Appendix IO MUX of ESP32 Series Datasheet for IO’s power domain. VDD is the I/O voltage for a particular power domain of pins. 2 For VDD3P3_CPU and VDD3P3_RTC power domain, per-pin current sourced in the same domain is gradually reduced from around 40 mA to around 29 mA, V OH >=2.64 V, as the number of current-source pins increases. 3 Pins occupied by flash and/or PSRAM in the VDD_SDIO power domain were excluded from the test. 6.4 Current Consumption Characteristics 6.4.1 Current Consumption in Active Mode Owing to the use of advanced power-management technologies, the module can switch between different power modes. For details on different power modes, please refer to Section RTC and Low-Power Management in ESP32 Series Datasheet. The current consumption measurements are taken with a 3.3 V supply at 25 °C ambient temperature. TX current consumption is rated at a 100% duty cycle. RX current consumption is rated when the peripherals are disabled and the CPU idle. Table 15: Current Consumption for Wi-Fi (2.4 GHz) in Active Mode Work Mode RF Condition Description Peak (mA) Active (RF working) TX 802.11b, 20 MHz, 1 Mbps, @19.5 dBm 368 802.11g, 20 MHz, 54 Mbps, @14 dBm 258 802.11n, 20 MHz, MCS7, @13 dBm 248 802.11n, 40 MHz, MCS7, @13 dBm 205 Cont’d on next page Espressif Systems 27 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 6 Electrical Characteristics Table 15 – cont’d from previous page Work Mode RF Condition Description Peak (mA) RX 802.11b/g/n, 20 MHz 111 802.11n, 40 MHz 117 6.4.2 Current Consumption in Other Modes Table 16: Current Consumption Depending on Work Modes Work mode Description Current consumption (Typ) Modem-sleep 1, 2 The CPU is powered on 3 240 MHz 30–68 mA 160 MHz 27–44 mA Normal speed: 80 MHz 20–31 mA Light-sleep — 0.8 mA Deep-sleep The ULP coprocessor is powered on 4 150 µA ULP sensor-monitored pattern 5 100 µA @1% duty RTC timer + RTC memory 10 µ A RTC timer only 5 µA Power off CHIP_PU is set to low level, the chip is powered off 1 µA 1 The current consumption figures in Modem-sleep mode are for cases where the CPU is powered on and the cache idle. 2 When Wi-Fi is enabled, the chip switches between Active and Modem-sleep modes. Therefore, current consumption changes accordingly. 3 In Modem-sleep mode, the CPU frequency changes automatically. The frequency depends on the CPU load and the peripherals used. 4 During Deep-sleep, when the ULP coprocessor is powered on, peripherals such as GPIO and RTC I2C are able to operate. 5 The ”ULP sensor-monitored pattern” refers to the mode where the ULP coprocessor or the sensor works periodically. When ADC works with a duty cycle of 1%, the typical current consumption is 100 µA. 6.5 Memory Specifications The data below is sourced from the memory vendor datasheet. These values are guaranteed through design and/or characterization but are not fully tested in production. Devices are shipped with the memory erased. Table 17: Flash Specifications Parameter Description Min Typ Max Unit VCC Power supply voltage (1.8 V) 1.65 1.80 2.00 V Power supply voltage (3.3 V) 2.7 3.3 3.6 V F C Maximum clock frequency 80 — — MHz — Program/erase cycles 100,000 — — cycles T RET Data retention time 20 — — years T P P Page program time — 0.8 5 ms Cont’d on next page Espressif Systems 28 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 6 Electrical Characteristics Table 17 – cont’d from previous page Parameter Description Min Typ Max Unit T SE Sector erase time (4 KB) — 70 500 ms T BE1 Block erase time (32 KB) — 0.2 2 s T BE2 Block erase time (64 KB) — 0.3 3 s T CE Chip erase time (16 Mb) — 7 20 s Chip erase time (32 Mb) — 20 60 s Chip erase time (64 Mb) — 25 100 s Chip erase time (128 Mb) — 60 200 s Chip erase time (256 Mb) — 70 300 s Espressif Systems 29 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 7 RF Characteristics 7 RF Characteristics This section contains tables with RF characteristics of the Espressif product. The RF data is measured at the antenna port, where RF cable is connected, including the front-end loss. Devices should operate in the center frequency range allocated by regional regulatory authorities. The target center frequency range and the target transmit power are configurable by software. See ESP RF Test Tool and Test Guide for instructions. Unless otherwise stated, the RF tests are conducted with a 3.3 V (±5%) supply at 25 ºC ambient temperature. 7.1 Wi-Fi Radio Table 18: Wi-Fi RF Characteristics Name Description Center frequency range of operating channel 2412 ~ 2484 MHz Wi-Fi wireless standard IEEE 802.11b/g/n 7.1.1 Wi-Fi RF Transmitter (TX) Characteristics Table 19: TX Power with Spectral Mask and EVM Meeting 802.11 Standards Min Typ Max Rate (dBm) (dBm) (dBm) 802.11b, 1 Mbps — 19.5 — 802.11b, 11 Mbps — 19.5 — 802.11g, 6 Mbps — 18.0 — 802.11g, 54 Mbps — 14.0 — 802.11n, HT20, MCS0 — 18.0 — 802.11n, HT20, MCS7 — 13.0 — 802.11n, HT40, MCS0 — 18.0 — 802.11n, HT40, MCS7 — 13.0 — Table 20: TX EVM Test 1 Min Typ Limit Rate (dB) (dB) (dB) 802.11b, 1 Mbps, DSSS — –26.5 –10.0 802.11b, 11 Mbps, CCK — –26.5 –10.0 802.11g, 6 Mbps, OFDM — –24.0 –5.0 802.11g, 54 Mbps, OFDM — –30.0 –25.0 802.11n, HT20, MCS0 — –24.0 –5.0 Cont’d on next page Espressif Systems 30 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 7 RF Characteristics Table 20 – cont’d from previous page Min Typ Limit Rate (dB) (dB) (dB) 802.11n, HT20, MCS7 — –30.5 –27.0 802.11n, HT40, MCS0 — –24.0 –5.0 802.11n, HT40, MCS7 — –30.5 –27.0 1 EVM is measured at the corresponding typical TX power provided in Table 19 Wi-Fi RF Transmitter (TX) Characteristics above. 7.1.2 Wi-Fi RF Receiver (RX) Characteristics For RX tests, the PER (packet error rate) limit is 8% for 802.11b, and 10% for 802.11g/n. Table 21: RX Sensitivity Min Typ Max Rate (dBm) (dBm) (dBm) 802.11b, 1 Mbps — –97.0 — 802.11b, 2 Mbps — –94.0 — 802.11b, 5.5 Mbps — –91.0 — 802.11b, 11 Mbps — –88.0 — 802.11g, 6 Mbps — –92.0 — 802.11g, 9 Mbps — –91.0 — 802.11g, 12 Mbps — –89.0 — 802.11g, 18 Mbps — –87.0 — 802.11g, 24 Mbps — –84.0 — 802.11g, 36 Mbps — –80.0 — 802.11g, 48 Mbps — –76.0 — 802.11g, 54 Mbps — –75.0 — 802.11n, HT20, MCS0 — –91.0 — 802.11n, HT20, MCS1 — –88.0 — 802.11n, HT20, MCS2 — –85.0 — 802.11n, HT20, MCS3 — -83.0 — 802.11n, HT20, MCS4 — –80.0 — 802.11n, HT20, MCS5 — –75.0 — 802.11n, HT20, MCS6 — –74.0 — 802.11n, HT20, MCS7 — –72.0 — 802.11n, HT40, MCS0 — –88.0 — 802.11n, HT40, MCS1 — –85.0 — 802.11n, HT40, MCS2 — –82.0 — 802.11n, HT40, MCS3 — –80.0 — 802.11n, HT40, MCS4 — –76.0 — 802.11n, HT40, MCS5 — –72.0 — 802.11n, HT40, MCS6 — –71.0 — Cont’d on next page Espressif Systems 31 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 7 RF Characteristics Table 21 – cont’d from previous page Min Typ Max Rate (dBm) (dBm) (dBm) 802.11n, HT40, MCS7 — –69.0 — Table 22: Maximum RX Level Min Typ Max Rate (dBm) (dBm) (dBm) 802.11b, 1 Mbps — 5 — 802.11b, 11 Mbps — 5 — 802.11g, 6 Mbps — 0 — 802.11g, 54 Mbps — -8 — 802.11n, HT20, MCS0 — 0 — 802.11n, HT20, MCS7 — -8 — 802.11n, HT40, MCS0 — 0 — 802.11n, HT40, MCS7 — -8 — Table 23: RX Adjacent Channel Rejection Min Typ Max Rate (dB) (dB) (dB) 802.11b, 11 Mbps — 35 — 802.11g, 6 Mbps — 27 — 802.11g, 54 Mbps — 13 — 802.11n, HT20, MCS0 — 27 — 802.11n, HT20, MCS7 — 12 — 802.11n, HT40, MCS0 — 16 — 802.11n, HT40, MCS7 — 7 — 7.2 Bluetooth Radio Table 24: Bluetooth LE RF Characteristics Name Description Center frequency range of operating channel 2402 ~ 2480 MHz RF transmit power range –12.0 ~ 9.0 dBm 7.2.1 Receiver – Basic Data Rate Espressif Systems 32 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 7 RF Characteristics Table 25: Receiver Characteristics – Basic Data Rate Parameter Conditions Min Typ Max Unit Sensitivity @0.1% BER — –90 –89 –88 dBm Maximum received signal @0.1% BER — 0 — — dBm Co-channel C/I — — +7 — dB Adjacent channel selectivity C/I F = F0 + 1 MHz — — –6 dB F = F0 – 1 MHz — — –6 dB F = F0 + 2 MHz — — –25 dB F = F0 – 2 MHz — — –33 dB F = F0 + 3 MHz — — –25 dB F = F0 – 3 MHz — — –45 dB Out-of-band blocking performance 30 MHz ~ 2000 MHz –10 — — dBm 2000 MHz ~ 2400 MHz –27 — — dBm 2500 MHz ~ 3000 MHz –27 — — dBm 3000 MHz ~ 12.5 GHz –10 — — dBm Intermodulation — –36 — — dBm 7.2.2 Transmitter – Basic Data Rate Table 26: Transmitter Characteristics – Basic Data Rate Parameter Conditions Min Typ Max Unit RF transmit power * — — 0 — dBm Gain control step — — 3 — dB RF power control range — –12 — +9 dBm +20 dB bandwidth — — 0.9 — MHz Adjacent channel transmit power F = F0 ± 2 MHz — –55 — dBm F = F0 ± 3 MHz — –55 — dBm F = F0 ± > 3 MHz — –59 — dBm ∆ f1 avg — — — 155 kHz ∆ f2 max — 127 — — kHz ∆ f2 avg /∆ f1 avg — — 0.92 — — ICFT — — –7 — kHz Drift rate — — 0.7 — kHz/50 µs Drift (DH1) — — 6 — kHz Drift (DH5) — — 6 — kHz * There are a total of eight power levels from 0 to 7, and the transmit power ranges from –12 dBm to 9 dBm. When the power level rises by 1, the transmit power increases by 3 dB. Power level 4 is used by default and the corresponding transmit power is 0 dBm. 7.2.3 Receiver – Enhanced Data Rate Espressif Systems 33 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 7 RF Characteristics Table 27: Receiver Characteristics – Enhanced Data Rate Parameter Conditions Min Typ Max Unit π/4 DQPSK Sensitivity @0.01% BER — –90 –89 –88 dBm Maximum received signal @0.01% BER — — 0 — dBm Co-channel C/I — — 11 — dB Adjacent channel selectivity C/I F = F0 + 1 MHz — –7 — dB F = F0 – 1 MHz — –7 — dB F = F0 + 2 MHz — –25 — dB F = F0 – 2 MHz — –35 — dB F = F0 + 3 MHz — –25 — dB F = F0 – 3 MHz — –45 — dB 8DPSK Sensitivity @0.01% BER — –84 –83 –82 dBm Maximum received signal @0.01% BER — — –5 — dBm C/I c-channel — — 18 — dB Adjacent channel selectivity C/I F = F0 + 1 MHz — 2 — dB F = F0 – 1 MHz — 2 — dB F = F0 + 2 MHz — –25 — dB F = F0 – 2 MHz — –25 — dB F = F0 + 3 MHz — –25 — dB F = F0 – 3 MHz — –38 — dB 7.2.4 Transmitter – Enhanced Data Rate Table 28: Transmitter Characteristics – Enhanced Data Rate Parameter Conditions Min Typ Max Unit RF transmit power (see note under Table 26) — — 0 — dBm Gain control step — — 3 — dB RF power control range — –12 — +9 dBm π/4 DQPSK max w0 — — –0.72 — kHz π/4 DQPSK max wi — — –6 — kHz π/4 DQPSK max |wi + w0| — — –7.42 — kHz 8DPSK max w0 — — 0.7 — kHz 8DPSK max wi — — –9.6 — kHz 8DPSK max |wi + w0| — — –10 — kHz π/4 DQPSK modulation accuracy RMS DEVM — 4.28 — % 99% DEVM — 100 — % Peak DEVM — 13.3 — % 8 DPSK modulation accuracy RMS DEVM — 5.8 — % 99% DEVM — 100 — % Peak DEVM — 14 — % In-band spurious emissions F = F0 ± 1 MHz — –46 — dBm Espressif Systems 34 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 7 RF Characteristics Parameter Conditions Min Typ Max Unit F = F0 ± 2 MHz — –44 — dBm F = F0 ± 3 MHz — –49 — dBm F = F0 +/– > 3 MHz — — –53 dBm EDR differential phase coding — — 100 — % 7.3 Bluetooth LE Radio 7.3.1 Receiver Table 29: Receiver Characteristics – Bluetooth LE Parameter Conditions Min Typ Max Unit Sensitivity @30.8% PER — –94 –93 –92 dBm Maximum received signal @30.8% PER — 0 — — dBm Co-channel C/I — — +10 — dB Adjacent channel selectivity C/I F = F0 + 1 MHz — –5 — dB F = F0 – 1 MHz — –5 — dB F = F0 + 2 MHz — –25 — dB F = F0 – 2 MHz — –35 — dB F = F0 + 3 MHz — –25 — dB F = F0 – 3 MHz — –45 — dB Out-of-band blocking performance 30 MHz ~ 2000 MHz –10 — — dBm 2000 MHz ~ 2400 MHz –27 — — dBm 2500 MHz ~ 3000 MHz –27 — — dBm 3000 MHz ~ 12.5 GHz –10 — — dBm Intermodulation — –36 — — dBm 7.3.2 Transmitter Table 30: Transmitter Characteristics – Bluetooth LE Parameter Conditions Min Typ Max Unit RF transmit power (see note under Table 26) — — 0 — dBm Gain control step — — 3 — dB RF power control range — –12 — +9 dBm Adjacent channel transmit power F = F0 ± 2 MHz — –55 — dBm F = F0 ± 3 MHz — –57 — dBm F = F0 ± > 3 MHz — –59 — dBm ∆ f1 avg — — — 265 kHz ∆ f2 max — 210 — — kHz ∆ f2 avg /∆ f1 avg — — +0.92 — — ICFT — — –10 — kHz Drift rate — — 0.7 — kHz/50 µs Drift — — 2 — kHz Espressif Systems 35 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 8 Peripheral Schematics 8 Peripheral Schematics This is the typical application circuit of the module connected with peripheral components (for example, power supply, antenna, reset button, JTAG interface, and UART interface). 5 5 4 4 3 3 2 2 1 1 D D C C B B A A PWR_EN U1TXD/IO19 U1RXD/IO22 INT_B/IO27 DBG_RXD/IO3 DBG_TXD/IO1 PWR_EN U1RXD/IO22 U1TXD/IO19 INT_B/IO27 DBG_RXD/IO3 DBG_TXD/IO1 PWR_EN INT_B/IO27 U1TXD/IO19 U1RXD/IO22 GND VCC3V3 GND GND VCC3V3 GND GND GND GND GND GND GND GND GND VCC3V3 GND GND VCC3V3 VCC3V3 GND Title Size Document Number Re v Date: Sheet o f #29932 1.0 ESP32-PICO-V3-ZERO-PERIPHERAL-BOARD B 3 3Wednesday, June 17, 2020 Title Size Document Number Re v Date: Sheet o f #29932 1.0 ESP32-PICO-V3-ZERO-PERIPHERAL-BOARD B 3 3Wednesday, June 17, 2020 Title Size Document Number Re v Date: Sheet o f #29932 1.0 ESP32-PICO-V3-ZERO-PERIPHERAL-BOARD B 3 3Wednesday, June 17, 2020 R10 TBD C4 10uF C2 0.1uF J6 CON3 1 2 3 R9 TBD U2 Host_MCU 1 2 3 4 C1 10uF R8 TBD SW1 1 1 2 2 C3 TBD R1 TBD C5 0.1uF U1 ESP32-PICO-V3-ZERO NC 1 NC 2 DBG_RXD/IO3 3 DBG_TXD/IO1 4 NC 5 NC 6 NC 7 NC 8 NC 9 NC 10 NC 11 GND 12 NC 13 NC 14 NC 15 NC 16 NC 17 NC 18 EN 19 GND 20 GND 21 VDD33 22 GND 23 GND 24 GND 25 GND 26 GND 27 GND 28 GND 29 GND 30 GND 31 GND 32 NC 33 NC 34 NC 35 NC 36 GND 37 NC 38 NC 39 NC 40 U1TXD/IO19 41 GND 42 VDD33 43 GND 44 U1RXD/IO22 45 NC 46 INT_B/IO27 47 NC 48 GND 49 GND 77 GND 50 GND 51 GND 52 GND 53 GND 54 GND 55 GND 56 GND 57 GND 58 GND 59 GND 60 GND 61 GND 62 GND 63 GND 64 GND 65 GND 66 GND 67 GND 68 GND 69 GND 70 GND 71 GND 72 GND 73 GND 74 GND 75 GND 76 J3 CON3 1 2 3 J4 CON2 1 2 R11 TBD R2 0R Figure 6: Peripheral Schematics • Soldering EPAD Pin 73 to the ground of the base board is not a must. If you choose to solder it, please apply the correct amount of soldering paste. Too much soldering paste may increase the gap between the module and the baseboard. As a result, the adhesion between other pins and the baseboard may be poor. • To ensure that the power supply to the ESP32 chip is stable during power-up, it is advised to add an RC delay circuit at the EN pin. The recommended setting for the RC delay circuit is usually R = 10 kΩ and C = Espressif Systems 36 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 8 Peripheral Schematics 1 µF. However, specific parameters should be adjusted based on the power-up timing of the module and the power-up and reset sequence timing of the chip. For ESP32’s power-up and reset sequence timing diagram, please refer to Section 4.6 Chip Power-up and Reset. • UART0 is used to download firmware and log output. When using the AT firmware, please note that the UART GPIO is already configured (refer to Hardware Connection). It is recommended to use the default configuration. Espressif Systems 37 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 9 Module Dimensions 9 Module Dimensions 16±0.15 23±0.15 0.8±0.1 2.3±0.15 14 13.8 Top view Side view Bottom view ESP32-PICO-V3-ZERO Module Dimensions Unit: mm Figure 7: Physical Dimensions Note: For information about tape, reel, and product marking, please refer to ESP32 Module Packaging Information. Espressif Systems 38 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 10 PCB Layout Recommendations 10 PCB Layout Recommendations 10.1 PCB Land Pattern This section provides the following resources for your reference: • Figures for recommended PCB land patterns with all the dimensions needed for PCB design. See Figure 8 Recommended PCB Land Pattern. • Source files of recommended PCB land patterns to measure dimensions not covered in Figure 8. You can view the source files for ESP32-PICO-V3-ZERO with Autodesk Viewer. • 3D models of ESP32-PICO-V3-ZERO. Please make sure that you download the 3D model file in .STEP format (beware that some browsers might add .txt). 16 23 5 5 0.6 1.2 1.2 16 0.6 15.4 13.8 12.4 11.6 10.8 15.4 13.8 12.4 11.6 10.8 Antenna Area Unit: mm : Pad Figure 8: Recommended PCB Land Pattern Espressif Systems 39 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 10 PCB Layout Recommendations 10.2 Module Placement for PCB Design To achieve the optimum RF performance on a device with on-board antenna, please follow the guidelines below. The module uses an inverted-F antenna design, and the antenna area of the module should have specific placement against the base board. The feed point of the antenna should be as close to the board as possible. The PCB antenna area should be placed outside the base board whenever possible while the module be put as close as possible to the edge of the base board. As is shown in Figure 9, examples 3 and 4 of the module position on the base board are highly recommended, while examples 1, 2, and 5 are not recommended.       ✅ ✅ Figure 9: Module Placement on a Base Board If the positions recommended above are not possible, then please make sure that the module is not covered by any metal shell and that a clearance area (without copper, routing, or components) outside the antenna is large enough, as shown in Figure 10. In addition, if there is base board under the antenna area, it is recommended to cut it off to minimize its impact on the antenna. Espressif Systems 40 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 10 PCB Layout Recommendations Min 7 Max 1 Base board Max 2 Unit: mm : Clearance Area Figure 10: Keepout Zone for Module’s Antenna on the Base Board If the PCB layout does not follow the above rules, then RF throughput and RF range testing should be performed to ensure that the end product performance is satisfactory. When designing an end product, pay attention to the impact of enclosure on the antenna and verify the device performance by making RF verification. Espressif Systems 41 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 10 PCB Layout Recommendations 10.3 Dimensions of RF Test Connector 2.30 2.30 1.92 0.60 1.35 IPEX Connector Part No.: 20549-001E Unit: mm Figure 11: Dimensions of RF Test Connector Espressif Systems 42 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 11 Product Handling 11 Product Handling 11.1 Storage Conditions The products sealed in moisture barrier bags (MBB) should be stored in a non-condensing atmospheric environment of < 40 °C and 90%RH. The module is rated at the moisture sensitivity level (MSL) of 3. After unpacking, the module must be soldered within 168 hours with the factory conditions 25 ± 5 °C and 60 %RH. If the above conditions are not met, the module needs to be baked. 11.2 Electrostatic Discharge (ESD) • Human body model (HBM): ±2000 V • Charged-device model (CDM): ±500 V 11.3 Reflow Profile Solder the module in a single reflow. 50 150 0 25 1 ~ 3 ℃/s 0 200 250 200 –1 ~ –5 ℃/s Cooling zone 100 217 50 100 250 Reflow zone 217 ℃ 60 ~ 90 s Temperature (℃) Preheating zone 150 ~ 200 ℃ 60 ~ 120 s Ramp-up zone Peak Temp. 235 ~ 250 ℃ Soldering time > 30 s Time (sec.) Ramp-up zone — Temp.: 25 ~ 150 ℃ Time: 60 ~ 90 s Ramp-up rate: 1 ~ 3 ℃/s Preheating zone — Temp.: 150 ~ 200 ℃ Time: 60 ~ 120 s Reflow zone — Temp.: >217 ℃ 60 ~ 90 s; Peak Temp.: 235 ~ 250 ℃ Time: 30 ~ 70 s Cooling zone — Peak Temp. ~ 180 ℃ Ramp-down rate: –1 ~ –5 ℃/s Solder — Sn-Ag-Cu (SAC305) lead-free solder alloy Figure 12: Reflow Profile Espressif Systems 43 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 11 Product Handling 11.4 Ultrasonic Vibration Avoid exposing Espressif modules to vibration from ultrasonic equipment, such as ultrasonic welders or ultrasonic cleaners. This vibration may induce resonance in the in-module crystal and lead to its malfunction or even failure. As a consequence, the module may stop working or its performance may deteriorate. Espressif Systems 44 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 Datasheet Versioning Datasheet Versioning Datasheet Version Status Watermark Definition v0.1 ~ v0.5 (excluding v0.5) Draft Confidential This datasheet is under development for products in the design stage. Specifications may change without prior notice. v0.5 ~ v1.0 (excluding v1.0) Preliminary release Preliminary This datasheet is actively updated for products in the verification stage. Specifications may change before mass production, and the changes will be documentation in the datasheet’s Revision History. v1.0 and higher Official release — This datasheet is publicly released for products in mass production. Specifications are finalized, and major changes will be communicated via Product Change Notifications (PCN). Any version — Not Recommended for New Design (NRND) 1 This datasheet is updated less frequently for products not recommended for new designs. Any version — End of Life (EOL) 2 This datasheet is no longer mtained for products that have reached end of life. 1 Watermark will be added to the datasheet title page only when all the product variants covered by this datasheet are not recommended for new designs. 2 Watermark will be added to the datasheet title page only when all the product variants covered by this datasheet have reached end of life. Espressif Systems 45 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 Related Documentation and Resources Related Documentation and Resources Related Documentation • ESP32 Series Datasheet – Specifications of the ESP32 hardware. • ESP32 Technical Reference Manual – Detailed information on how to use the ESP32 memory and peripherals. • ESP32 Hardware Design Guidelines – Guidelines on how to integrate the ESP32 into your hardware product. • ESP32 ECO and Workarounds for Bugs – Correction of ESP32 design errors. • ESP32 Series SoC Errata – Descriptions of known errors in ESP32 series of SoCs. • Certificates https://espressif.com/en/support/documents/certificates • ESP32 Product/Process Change Notifications (PCN) https://espressif.com/en/support/documents/pcns • ESP32 Advisories – Information on security, bugs, compatibility, component reliability. https://espressif.com/en/support/documents/advisories • Documentation Updates and Update Notification Subscription https://espressif.com/en/support/download/documents Developer Zone • ESP-IDF Programming Guide for ESP32 – Extensive documentation for the ESP-IDF development framework. • ESP-IDF and other development frameworks on GitHub. https://github.com/espressif • ESP32 BBS Forum – Engineer-to-Engineer (E2E) Community for Espressif products where you can post questions, share knowledge, explore ideas, and help solve problems with fellow engineers. https://esp32.com/ • The ESP Journal – Best Practices, Articles, and Notes from Espressif folks. https://blog.espressif.com/ • See the tabs SDKs and Demos, Apps, Tools, AT Firmware. https://espressif.com/en/support/download/sdks-demos Products • ESP32 Series SoCs – Browse through all ESP32 SoCs. https://espressif.com/en/products/socs?id=ESP32 • ESP32 Series Modules – Browse through all ESP32-based modules. https://espressif.com/en/products/modules?id=ESP32 • ESP32 Series DevKits – Browse through all ESP32-based devkits. https://espressif.com/en/products/devkits?id=ESP32 • ESP Product Selector – Find an Espressif hardware product suitable for your needs by comparing or applying filters. https://products.espressif.com/#/product-selector?language=en Contact Us • See the tabs Sales Questions, Technical Enquiries, Circuit Schematic & PCB Design Review, Get Samples (Online stores), Become Our Supplier, Comments & Suggestions. https://espressif.com/en/contact-us/sales-questions Espressif Systems 46 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 Revision History Revision History Date Version Release notes 2025-10-20 v1.6 • Section 2 Block Diagram: Added a note about pin mapping between the chip and the in-package flash/PSRAM • Updated Figure 3 Visualization of Timing Parameters for the Strapping Pins • Added Section 4.6 Chip Power-up and Reset • Table 14 DC Characteristics (3.3 V, 25 °C): Added V IH_nRST • Added Section 6.5 Memory Specifications • Added Section Datasheet Versioning 2025-01-24 v1.5 • Improved the wording and structure of following sections: – Updated Section ”Description” and renamed to Series Comparison – Updated Section ”Strapping Pins” and renamed to Boot Configurations – Updated Table ”Wi-Fi RF Standards” and renamed to Wi-Fi RF Char- acteristics • Added notes about erase cycles and retention time for flash in Table 1 Series Comparison • Added notes about antenna keepout zone in Section 3.1 Pin Layout • Added Chapter 5 Peripherals • Added a note about UART in Section 8 Peripheral Schematics 2023-08-29 v1.4 • Added Section ”Strapping Pins” • Section 8 Peripheral Schematics: Added a note about EPAD soldering • Section 10.1 PCB Land Pattern: Added source files of PCB land patterns and 3D models of the module • Added Section 11.4 Ultrasonic Vibration 2022-02-22 v1.3 • Added a note regarding the RF test connector in Section 1.1 Features • Updated Figure 1 ESP32-PICO-V3-ZERO Block Diagram, Table 14 DC Char- acteristics (3.3 V, 25 °C), and Table 18 Wi-Fi Radio 2021-11-08 v1.2 • Added a note below Figure 7 Physical Dimensions • Updated Table 13 Recommended Operating Conditions • Upgraded document formatting 2021-02-09 v1.1 • Deleted Reset Circuit and Discharge Circuit for VDD33 Rail in Section 8 Peripheral Schematics • Modified the note below Figure 12 Reflow Profile 2020-11-03 v1.0 First release Espressif Systems 47 Submit Documentation Feedback ESP32-PICO-V3-ZERO Datasheet v1.6 Disclaimer and Copyright Notice Information in this document, including URL references, is subject to change without notice. ALL THIRD PARTY’S INFORMATION IN THIS DOCUMENT IS PROVIDED AS IS WITH NO WARRANTIES TO ITS AUTHENTICITY AND ACCURACY. NO WARRANTY IS PROVIDED TO THIS DOCUMENT FOR ITS MERCHANTABILITY, NON-INFRINGEMENT, FITNESS FOR ANY PARTICULAR PURPOSE, NOR DOES ANY WARRANTY OTHERWISE ARISING OUT OF ANY PROPOSAL, SPECIFICATION OR SAMPLE. All liability, including liability for infringement of any proprietary rights, relating to use of information in this document is disclaimed. No licenses express or implied, by estoppel or otherwise, to any intellectual property rights are granted herein. The Wi-Fi Alliance Member logo is a trademark of the Wi-Fi Alliance. The Bluetooth logo is a registered trademark of Bluetooth SIG. All trade names, trademarks and registered trademarks mentioned in this document are property of their respective owners, and are hereby acknowledged. Copyright © 2025 Espressif Systems (Shanghai) Co., Ltd. All rights reserved. www.espressif.com