ESP examples

Examples are split into different CPU architectures. Currently you can find examples for:

• Visual Studio: All examples will be always released for Visual studio, due to the fact that library is developed in it. You can run examples with NodeMCU hardware or any other hardware, if you connect it to USB and run with AT commands
• POSIX: Some examples will be added for Linux (or other POSIX compliant platforms). You can run examples with ESP devices connected to USB-TTL adapters or single board computers (e.g. Raspberry Pi).
• STM32-Discovery: Small amount of examples are available for STM32 based Discovery boards which come with socket for ESP-01 device. Examples are written in Atollic TrueSTUDIO (GCC compiler), Keil uVision (MDK-ARM compiler) and IAR.

ESP requirements

In order to run the examples, ESP device must run the AT software provided from Espressif systems. Please check official documentation for detailed requirements to run this library with you ESP8266 device.

WIN32 Examples

All windows based examples are written in Visual Studio 2017 as "Win32 project" and "Console Application".

Visual Studio configuration

It may happen that Visual Studio sets different configuration on first project load and this may lead to wrong build and possible errors. Active configuration must be Debug and Win32 or x86. Default active build can be set in project settings.

NodeMCU development board

For development purposes, NodeMCU v3 board was used with virtual COM port support to translate USB communication to UART required for ESP8266.

Some NodeMCU boards have CH340 USB->UART transceiver where I found problems with communication due to data loss between ESP and PC even at 115200 bauds. Try to find NodeMCU with something else than CH340.

System functions for WIN32

Required system functions are based on "windows.h" file, available on windows operating system. Natively, there is support for:

1. Timing functions
2. Semaphores
3. Mutexes
4. Threads

The last part are message queues which are not implemented in Windows OS. Message queues were developed with help of semaphores and dynamic memory allocatations. System port for WIN32 is available in esp_sys_win32.c file.

Communication with WIN32

Communication with NodeMCU hardware is using virtual files for COM ports. Implementation of low-level part (together with memory allocation for library) is available in esp_ll_win32.c file.

In order to start using this port, user must set the appropriate COM port name when opening a virtual file. Please check implementation file for details.

POSIX Examples

All POSIX examples are using CMake build system and can be built either native or cross-compile with the following instructions:

cd ${EXAMPLE_PROJECT_DIRECTORY}
mkdir build && cd build # Create a build directory
cmake .. && make -j$(nproc)

System functions for POSIX

This port utilized pthread library:

1. Mutexes
2. Semaphores
3. Threads

as well as <time.h> for:

1. SysTick
2. Timed Semaphores

POSIX message queue are too powerful for this, so the same implementation as Windows is used.

Communication with POSIX system

Communication with NodeMCU hardware is done by using POSIX APIs through /dev/ttyXYZ character device. Implementation of low-level part (together with memory allocation for library) is available in esp_ll_posix.c file.

The communication serial port may also needs to be altered if necessary, just like Windows port does.

STM32F769I-Discovery

Use connector CN2 to connect ESP-01 module with the board

Detailed pinout for STM32F769I-Discovery board

ESP-01 connection
- ESP_RX:           PC12
- ESP_TX:           PD2
- ESP_RESET:        PJ14

- UART:             UART5
- UART DMA:         DMA1
- UART DMA STREAM:  DMA_STREAM_0
- UART DMA CHANNEL: DMA_CHANNEL_4

DEBUG UART, connected through ST-LinkV2/1
- UART:             USART1
- UART_TX:          PA9
- UART_RX:          PA10
- UART baudrate:    921600

Driver implementation is available in esp_ll_stm32f769i_discovery.c

STM32F723E-Discovery

Use connector CN14 to connect ESP-01 module with the board

Detailed pinout for STM32F723E-Discovery board

ESP-01 connection
- ESP_RX:           PC12
- ESP_TX:           PD2
- ESP_RESET:        PG14
- ESP_CH_PD:        PD3
- ESP_GPIO_2:       PD6

- UART:             UART5
- UART DMA:         DMA1
- UART DMA STREAM:  DMA_STREAM_0
- UART DMA CHANNEL: DMA_CHANNEL_4

DEBUG UART, connected through ST-LinkV2/1
- UART:             USART6
- UART_TX:          PC6
- UART_RX:          PC7
- UART baudrate:    921600

Driver implementation is available in esp_ll_stm32f723e_discovery.c file.

STM32L496G-Discovery

Discovery comes with STMOD+ extensions board which includes connector marked as ESP-01.

Detailed pinout for STM32L496G-Discovery board

ESP-01 connection
- ESP_RX:           PB6
- ESP_TX:           PG10, pin connected on VDDIO2 domain, make sure it is enabled in PWR registers
- ESP_RESET:        PB2
- ESP_CH_PD:        PA4
- ESP_GPIO_0:       PH0
- ESP_GPIO_2:       PA0

- UART:             USART1
- UART DMA:         DMA1
- UART DMA CHANNEL: DMA_CHANNEL_5
- UART DMA REQUEST: DMA_REQUEST_2

DEBUG UART, connected through ST-LinkV2/1
- UART:             USART2
- UART_TX:          PA2
- UART_RX:          PD6
- UART baudrate:    921600

Driver implementation is available in esp_ll_stm32l496g_discovery.c

STM32L432KC-Nucleo

Detailed pinout for STM32L432KC-Nucleo board

ESP-01 connection
- ESP_RX:           PA9
- ESP_TX:           PA10
- ESP_RESET:        PA12
- ESP_CH_PD:        PB0
- ESP_GPIO_0:       PA7
- ESP_GPIO_2:       PA6

- UART:             USART1
- UART DMA:         DMA1
- UART DMA CHANNEL: DMA_CHANNEL_5
- UART DMA REQUEST: DMA_REQUEST_2

DEBUG UART, connected through ST-LinkV2/1
- UART:             USART2
- UART_TX:          PA2
- UART_RX:          PA3
- UART baudrate:    921600

Driver implementation is available in esp_ll_stm32l432kc_nucleo.c