ESP32 Reference

Usage

Firmware

  • Pre-compiled binary firmware files are in folder firmware.

    • boot_app0.bin

    • bootloader.bin

    • default.bin

    • ESP32_Sandbox.ino.bin

  • Or you can compile from source code in src with ESP-IDF and arduino-esp32.

    1. Setup ESP-IDF as described in its page (example on Debian).

      # 1.1 install compiler(toolchain)
sudo apt-get install gcc git wget make libncurses-dev flex bison gperf python python-serial
wget https://dl.espressif.com/dl/xtensa-esp32-elf-linux64-1.22.0-80-g6c4433a-5.2.0.tar.gz -O xtensa-esp32.tar.gz
tar -xvzf xtensa-esp32.tar.gz
# 1.2 set toolchains path in environment
echo PATH="\$PATH:$(pwd)/xtensa-esp32-elf/bin" ~/.profile
# 1.3 get and config ESP-IDF(headers and libs)
git clone --recursive https://github.com/espressif/esp-idf.git
cd esp-idf && git submodule update --init --recursive
echo IDF_PATH=$(pwd) >> ~/.profile

    2. Setup arduino-esp32 as one of ESP-IDF components.

      # 2.1 setup arduino-esp32
cd ${IDF_PATH}/examples && mkdir arduino-core && cd arduino-core
mkdir -p components && cd components && \
git clone https://github.com/espressif/arduino-esp32.git arduino && \
cd arduino && git submodule update --init --recursive && cd ../..
# 2.2 create a new project folder
MyProjectName=esp32-embci
mkdir -p ${MyProjectName}/main && cd ${MyProjectName}
sed 's/blink/${MyProjectName}.ino/g' "../../get-started/blink/Makefile" > Makefile
ln -s ../components components
echo "#include <Arduino.h>" > main/main.cpp

    3. Then compile with command make menuconfig && make all.

      # 3.1 add access to source file
rm -rf main
ln -s ${EMBCI_PATH}/files/esp32/src ./main
# 3.2 remember to tick on "Autostart Arduino setup and loop on boot"
make menuconfig && make all
# 3.3 copy generated binary files into folder `firmware`
ln -s ${EMBCI_PATH}/files/esp32/firmware ./firmware
cd build
cp ota_data_initial.bin ../firmware/boot_app0.bin
cp bootloader/bootloader.bin ESP32_Sandbox.ino.bin default.bin ../firmware/

Flash firmware

Use script EmBCI/tools/esptool.py or simply type command make flash to write binary files into on-shield ESP32. Use sudo if needed.

ESP32 serial monitor

miniterm.py /dev/ttyS1 115200
# or
screen /dev/ttyS1 115200
# Change port to `/dev/ttyS2` on OPi0+2. Or use our simple Makefile.
make monitor

or any other serial monitor.

Command Interface (Deprecated in v0.1.4)

Example output of serial.

ESP32 Firmware XXXX.XX-EmBCI
Board:  OrangePi Zero Plus [2]
Shield: EmBCI Rev.XX XXX XX XXXX
Booting...
...
Press `h` for help message
...
Supported commands:
    h - print this Help message
    c - Clear spi fifo queue
    d - change esp output Data source
    m - be less verbose (Mute)
    s - print Summary of current status
    v - be more Verbose
    w - turn on/off serial-to-Wifi redirection

Console-like Interface (Added in v0.1.5)

Example output of serial.

--- Miniterm on /dev/ttyUSB0  115200,8,N,1 ---
--- Quit: Ctrl+] | Menu: Ctrl+T | Help: Ctrl+T followed by Ctrl+H ---
rst:0x1 (POWERON_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
...
E (30) EmBCI: IDF Version: v3.2-dev-1385-g129d327
E (30) EmBCI: Chip info:
E (30) EmBCI:   model: ESP32
E (30) EmBCI:   cores: 2
E (40) EmBCI:   feature: /802.11bgn/BLE/BT/External-Flash: 4 MB
E (40) EmBCI:   revision number: 1
E (50) EmBCI: Firmware Version: 2019.4-EmBCI
E (50) EmBCI: ARM Board: OrangePi Zero Plus 2
E (50) EmBCI: EmBCI Shield: EmBCI Rev.B1 Apr 12 2019
...
I (1220) EmBCI: Type `help` for commands message
EmBCI> help
help
  Print the list of registered commands

sample_rate  [-r <0-6|250|500|1k|2k|4k|8k|16k>]
  Print or set ADS1299 sample rate
  -r, --rate=<0-6|250|500|1k|2k|4k|8k|16k>  specify sample rate (250-16000) or its index (0-6)

input_source  [-s <0-5|Normal|BIAS|Shorted|MVDD|Temperature|Test>] [-c <0-7>]
  Print or set ADS1299 data source
  -s, --source=<0-5|Normal|BIAS|Shorted|MVDD|Temperature|Test>  specify source name or its index (0-5)
  -c, --channel=<0-7>  specify channel number, default all

bias  [<on|off>] [-c <0-7>]
  Print or set ADS1299 BIAS output state
      <on|off>  action can also be <true|false>
  -c, --channel=<0-7>  specify channel number, default all

impedance  [<on|off>] [-c <0-7>]
  Print or set ADS1299 impedance measurement
      <on|off>  action can also be <true|false>
  -c, --channel=<0-7>  specify channel number, default all

sleep  [-t <t>] [-p <n>]... [-l <0|1>]... [--method=<light/deep>]
  Turn ESP32 into light/deep sleep mode
  -t, --time=<t>  wakeup time, ms
  -p, --gpio=<n>  If specified, wakeup using GPIO with given number
  -l, --level=<0|1>  GPIO level to trigger wakeup
  --method=<light/deep>  sleep method

...

summary
  Print summary of current status

tasks
  Get information about running RTOS tasks

Pin-out

On-shield ESP32-WROOM-32 connection with OrangePi Zero Plus(2) listed as follows.

Connection

ESP32

OPi0+

OPi0+2

EN

PA19

PA19

BOOT

PA18

PA18

DRDY

PA07

PD11

UART0

UART1

UART2

UART1

UART2

HSPI

SPI1

SPI1

OPi0+ Pin Number

num

UART1

UART2

SPI1

GPIO

T198 R199

T0 R1

CS13 CLK14 MO15 MI16

PIN

PG06 PG07

PA00 PA01

PA13 PA14 PA15 PA16

OPi0+2 Pin Number

num

UART2

SPI1

GPIO

T0 R1

CS13 CLK14 MO15 MI16

PIN

PA00 PA01

PA13 PA14 PA15 PA16

ESP32 Pin Number

num

EN

BOOT

DRDY

UART0

UART1

HSPI

GPIO

–

0

4

T1 R3

T10 R9

CS15 CLK14 MI12 MO13

PIN

3

25

26

35 34

18 17

CS23 CLK13 MI14 MO16
ESP32 Pin-out