Espressif Systems ESP User Manual

5.2.2 According to the schematic of ESP32-LyraT-Mini, the analog output of the ES8311 codec
chip is connected to the input of the ES7243 ADC chip. What is the purpose of this? . . . 154
5.2.3 When using the ESP32-MINI-1 module, the serial port printed the follows log when pow-
ered on. What could be the reason? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154
5.3 Hardware design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
5.3.1 The I2S pins of ESP32 are scattered. Can I route I2S signals to adjacent pins? For exam-
ple, to GPIO5, GPIO18, GPIO23, GPIO19, and GPIO22, or to GPIO25,
GPIO26, GPIO32, and GPIO33. . . . . . . . . . . . . . . . . . . . . . . . . . . 155
5.3.2 How can I stop the power loss of VDD3P3_RTC after ESP32 enters Light-sleep mode? . 155
5.3.3 What should be noted when I con󰝘gure the pins of ESP32? . . . . . . . . . . . . . . . . 155
5.3.4 What is the voltage tolerance of GPIOs of ESP chips? . . . . . . . . . . . . . . . . . . . 156
5.3.5 What are the power supply speci󰝘cations for ESP8266? . . . . . . . . . . . . . . . . . . 156
5.3.6 Do Espressif Wi-Fi modules support single-layer PCBs? . . . . . . . . . . . . . . . . . . 156
5.3.7 What should be noted when I power ESP8266 with batteries? . . . . . . . . . . . . . . . 156
5.3.8 Where can I get the footprint of ESP32 Series? . . . . . . . . . . . . . . . . . . . . . . . 156
5.3.9 For ESP32-S2 chips, can I have audio connection when the DVP camera interface is in use?157
5.3.10 What should be noted when I assign I2C signals to GPIO0 and GPIO4 of ESP32 modules? 157
5.3.11 When the external 󰝙ash is connected to GPIO6 ~ GPIO11, can they be set as SPI pins? . . 157
5.3.12 Do I need to connect an external crystal when using the ESP8285 chip? . . . . . . . . . . 157
5.3.13 Where can I 󰝘nd the reference design for connecting an external PSRAM to ESP32-D2WD?157
5.3.14 Can I use ESP32 to play music with PWM or DAC? . . . . . . . . . . . . . . . . . . . . 157
5.3.15 Why is the suggested voltage range of ESP32 modules di󰝗rent from that of ESP32 chips? 158
5.3.16 Why does it take a longer time to erase the 󰝙ash of self-developed modules than that of
Espressif modules? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158
5.3.17 Why does the current surge when ESP8266 is powered on? . . . . . . . . . . . . . . . . 158
5.3.18 What choices do I have when con󰝘guring the RMII clock for the Ethernet of ESP32? . . . 158
5.3.19 What kind of socket is used on ESP32-LyraT development boards to connect a speaker? . 158
5.3.20 For modules housing ESP32, which pins cannot be set by users? . . . . . . . . . . . . . . 159
5.3.21 Which is the reset pin of ESP32? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
5.3.22 What should be noted when I design the power supply for ESP8266? . . . . . . . . . . . 159
5.3.23 When I use the TOUT pin of ESP8266 to collect ADC sample signals, will the pins be
damaged if the voltage is greater than 1.0 V? . . . . . . . . . . . . . . . . . . . . . . . . 159
5.3.24 For modules with PCB antennas, what should be noted when I design the PCB and the
housing of the antenna? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
5.3.25 Can GPIO 34 ~ GPIO39 of ESP32 be used as UART RX pins? . . . . . . . . . . . . . . 159
5.3.26 Where can I 󰝘nd the design reference for the external 32 kHz crystal of ESP32 modules? . 160
5.3.27 Does the 󰝙ash of ESP32 modules support 80 MHz QIO access mode? . . . . . . . . . . . 160
5.3.28 How to con󰝘gure the RMII synchronous clock for the Ethernet of ESP32? . . . . . . . . . 160
5.3.29 How can I hard reset ESP8266? Is hard reset active low or active high? What are the
requirements for reset? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160
5.3.30 What does the term NC mean in Espressif schematics? . . . . . . . . . . . . . . . . . . . 160
5.3.31 How can I use multiple antennas with ESP32-S2? . . . . . . . . . . . . . . . . . . . . . 160
5.3.32 Does ESP32-C3F SPI CS0 pin need an external 10 kΩ pull-up resistor? . . . . . . . . . . 161
5.3.33 Is there any hardware design reference for ESP-Skainet Speech Recognition? . . . . . . . 161
5.3.34 Is it necessary to connect a 32 kHz RTC crystal? . . . . . . . . . . . . . . . . . . . . . . 161
5.3.35 For the ESP32-MINI-1 module, is there a component library for Altium Designer? . . . . 161
5.3.36 Can I change the input voltage of UART0 of ESP8266 from 3.3 V to 1.8 V? . . . . . . . 162
5.3.37 Is the level of UART0 of ESP8266 determined by VDD (VCC_WIFI) or VDDPST
(VCC_CODEC_IO)? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
5.3.38 What should be noted when I connect an external PSRAM to ESP32-D2WD? . . . . . . . 162
5.3.39 When the VDD power supply of ESP32 slowly rises from 0 V to 3.3 V, why does the chip
not start as usual? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
5.3.40 When using the ESP32-WROOM-32D module, can I set GPIO12 for other uses? . . . . . 162
5.3.41 When connecting an external 󰝙ash to ESP32-WROOM-32D module, is it possible if I do
not use GPIO6 ~ GPIO11 pins? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163
5.3.42 Do I need to add a shielding case to the PCB of ESP32 modules? . . . . . . . . . . . . . 163
5.3.43 Do I must use GPIO0, GPIO1, or GPIO3 of ESP32 as the I2S CLK pin? . . . . . . . . . 163
5.3.44 Does the ESP32-U4WDH chip support external PSRAM chips? . . . . . . . . . . . . . . 163
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Espressif Systems ESP Specifications

General

Brand	Espressif Systems
Model	ESP
Category	Motherboard
Language	English