- Generated on Tue Nov 24 2020 19:46:59 by
1.8.17
RIOT-OS port for Espressif's ESP8266 / ESP8285 MCUs. More...
RIOT-OS port for Espressif's ESP8266 / ESP8285 MCUs.
RIOT-Xtensa-ESP is a bare metal implementation of RIOT-OS for ESP8266 / ESP8285 SOCs which supports most features of RIOT-OS. The peripheral SPI and I2C interfaces allow to connect all external hardware modules supported by RIOT-OS, such as sensors and actuators. SPI interface can also be used to connect external IEEE802.15.4 modules to integrate ESP8266 boards into a GNRC network.
The RIOT-OS port for ESP8266 supports ESP8266 as well as ESP8285 MCUs and requires the ESP8266 RTOS SDK v3.x. To build a RIOT application, simply use the make command and specify an existing ESP8266 board, for example:
For more information about the make command variables and specific compile options, see section Compile Options.
Although the port does not use the official ESP8266 RTOS SDK directly, it must be installed for compilation. The reason is that the port uses most of the ESP8266 SOC definitions provided by SDK header files. In addition, it needs the hardware abstraction library (libhal), and ESP8266 WiFi stack binary libraries which are part of the SDK.
ESP8266 is a low-cost, ultra-low-power, single-core SoCs with an integrated WiFi module from Espressif Systems. The processor core is based on the Tensilica Xtensa Diamond Standard 106Micro 32-bit Controller Processor Core, which Espressif calls L106. The key features of ESP8266 are:
The following table gives a short reference of all board configuration parameters used by the ESP8266 port in alphabetical order.
| Parameter | Short Description | Type* |
|---|---|---|
| I2C0_SPEED | Bus speed of I2C_DEV(0) | o |
| I2C0_SCL | GPIO used as SCL for I2C_DEV(0) | o |
| I2C0_SDA | GPIO used as SCL for I2C_DEV(0) | o |
| I2C1_SPEED | Bus speed of I2C_DEV(1) | o |
| I2C1_SCL | GPIO used as SCL for I2C_DEV(1) | o |
| I2C1_SDA | GPIO used as SCL for I2C_DEV(1) | o |
| PWM0_GPIOS | GPIOs that can be used at channels of PWM_DEV(0) | o |
| SPI0_CS0 | GPIO used as default CS for SPI_DEV(0) | o |
*Type: m - mandatory, o - optional
The following table gives a short reference in alphabetical order of modules that can be enabled/disabled by board configurations and/or application's makefile using USEMODULE and DISABLE_MODULE.
| Module | Default | Short description |
|---|---|---|
| esp_gdb | not used | enable the compilation with debug information for debugging |
| esp_gdbstub | not used | enable the compilation of the gdbstub interface |
| esp_idf_heap | not used | use SDK heap implementation |
| esp_now | not used | enable the ESP-NOW network device |
| esp_qemu | not used | generate image for QEMU and GDB debugging |
| esp_spiffs | not used | enable SPIFFS for on-board flash memory |
| esp_wifi | not used | enable the Wifi network device |
| esp_wifi_ap | not used | enable the Wifi SoftAP network device |
| MCU | ESP8266EX |
|---|---|
| Vendor | Espressif |
| Cores | 1 x Tensilica Xtensa LX106 |
| FPU | no |
| RAM | 80 kByte user-data RAM 32 kByte instruction RAM 32 kByte instruction cache 16 kByte EST system-data RAM |
| Flash | 512 kByte ... 16 MByte |
| Frequency | 80 MHz or 160 MHz |
| Power Consumption | 70 mA in normal operating mode 20 uA in deep sleep mode |
| Timers | 1 x 32 bit |
| ADCs | 1 x 10 bit (1 channel) |
| GPIOs | 16 |
| I2Cs | 2 (software implementation) |
| SPIs | 2 |
| UARTs | 1 (console) + 1 transmit-only |
| WiFi | IEEE 802.11 b/g/n built in |
| Vcc | 2.5 - 3.6 V |
| Datasheet | Datasheet |
| Technical Reference | Technical Reference |
The following software components are required for compilation:
esptool.pyThere are two options to install the toolchain:
In both cases, the ESP flash programmer tool esptool.py is required, see section Installation of esptool.py.
The easiest way to install the toolchain is to use RIOT Docker riotdocker. The compilation process using RIOT Docker consists of two steps
make BOARD=...make flash-only BOARD=...where step 2 requires that the ESP flash programmer tool esptool.py is installed. Both steps can also be performed with a single command on the host system using the BUILD_IN_DOCKER variable:
Using RIOT Docker requires at least the following software components:
riotdocker)esptool.pyFor information about installing Docker on your host, refer to the appropriate manuals for your operating system. The easiest way to install Docker on an Ubuntu/Debian system is for example:
For information on how to install esptool.py, see section Installation of esptool.py.
The easiest way to use RIOT Docker is to use an existing riotdocker image. You can either pull and start the schorcht/riotbuild_esp8266_rtos Docker image which only contains the toolchain for ESP8266 RTOS SDK using
or the riot/riotbuild Docker image (size is about 1.5 GB) which contains the toolchains for all platforms using
Alternatively, you can generate the riotdocker image by yourself. A riotdocker fork that only installs the toolchain for ESP8266 RTOS SDK is available at GitHub. After cloning this repository, checkout branch esp8266_only_rtos_sdk to generate a Docker image with a size of "only" 890 MByte:
A riotdocker version that contains toolchains for all platforms supported by RIOT can be found at GitHub. However, the Docker image generated from this Docker file has a size of about 1.5 GByte.
Once the Docker image has been created, it can be started with the following commands while in the RIOT root directory:
/path/to/RIOT becomes visible as the home directory of the riotbuild user in the Docker. That is, the output of compilations in RIOT Docker are also accessible on the host system.Please refer the RIOT wiki on how to use the Docker image to compile RIOT OS.
Using RIOT Docker, the make process consists of the following two steps:
Once the according RIOT Docker image has been started from RIOT's root directory, a RIOT application can be compiled inside RIOT Docker using the make command as usual, for example:
This will generate a RIOT binary in ELF format.
flash target inside RIOT Docker.The RIOT binary has to be flash outside RIOT Docker on the host system. Since the RIOT Docker image was started while in RIOT's root directory, the output of the compilations is also accessible on the host system. On the host system, the flash-only target can then be used to flash the binary.
BUILD_IN_DOCKER variable: A more difficult way to install the toolchain is the manual installation of all required components as described below.
build-essential, cppcheck, coccinelle, curl, doxygen, git, graphviz, make, pcregrep, python, python-serial, python3, python3-flake8, unzip, wgetThe Xtensa GCC compiler for ESP8266 configured for use with RIOT-OS can be downloaded and installed as precompiled binary archive from GitHub:
Once the compiler is installed, you have to expand your PATH variable by the directory with Xtensa GCC binaries:
To compile RIOT-OS with the ESP8266 RTOS SDK, a modified version of the SDK is required. This modified version can also be downloaded as GIT repository.
To use the installed ESP8266 RTOS SDK, set the environment variable ESP8266_RTOS_SDK_DIR.
The RIOT port does not work with the esptool.py ESP flasher program available on GitHub or as package for your OS. Instead, a modified version from the ESP8266 RTOS SDK is required.
To avoid the installation of the complete ESP8266 RTOS SDK, for example because RIOT Docker riotdocker is used for compilation, esptool.py has been extracted from the ESP8266 RTOS SDK and placed in RIOT's directory dist/tools/esptool. For convenience, the build system uses always the version from this directory.
Therefore, it is not necessary to install esptool.py explicitly. However esptool.py depends on pySerial which can be installed either using pip
or the package manager of your OS, for example on Debian/Ubuntu systems:
For more information on esptool.py, please refer the git repository.
Once you have installed all required components, you should have the following directories.
To use the toolchain, please ensure that your environment variables are set correctly to
The compilation process can be controlled by following make variables:
| Option | Values | Default | Description |
|---|---|---|---|
| FLASH_MODE | dout, dio, qout, qio | dout | Set the flash mode, please take care with your module, see section Flash Modes |
| PORT | /dev/<port> | /dev/USB0 | Set the USB port for flashing the firmware |
Optional features of ESP8266 can be enabled using USEMODULE definitions in the makefile of the application. These are:
| Module | Description |
|---|---|
| esp_gdb | Enable the compilation with debug information |
| esp_gdbstub | Enable the compilation of the gdbstub interface for debugging with GDB |
| esp_idf_heap | Enable SDK heap implementation which provides remaining IRAM as additional heap region |
| esp_now | Enable the built-in WiFi module with the ESP-NOW protocol as netdev network device |
| esp_qemu | Enable the compilation of an QEMU image for debugging with GDB |
| esp_spiffs | Enable the SPIFFS drive in on-board flash memory |
| esp_sw_timer | Enable software timer implementation |
| esp_wifi | Enable the built-in WiFi module in infrastructure mode as netdev network device |
| esp_wifi_ap | Enable the built-in WiFi SoftAP module as netdev network device |
For example, to activate the SPIFFS drive in on-board flash memory, the makefile of application has simply to add the esp_spiffs module to USEMODULE make variable:
Modules can also be activated temporarily at the command line when calling the make command:
The FLASH_MODE make command variable determines the mode that is used for flash access in normal operation.
The flash mode determines whether 2 data lines (dio and dout) or 4 data lines (qio and qout) for addressing and data access. For each data line, one GPIO is required. Therefore, using qio or qout increases the performance of SPI Flash data transfers, but uses two additional GPIOs (GPIO9 and GPIO10). That is, in this flash modes these GPIOs are not available for other purposes. If you can live with lower flash data transfer rates, you should always use dio or dout to keep GPIO9 and GPIO10 free for other purposes.
For more information about these flash modes, refer the documentation of esptool.py.
qio, qout, dio and dout, ESP8285 modules have to be always flashed in dout mode. The default flash mode is dout.The flash memory of ESP8266 can be erased completely with following command:
ESP8266 has 17 GPIO pins, which are all digital pins. Some of them can not be used at all or have bootstrapping capabilities and are therefore not available on all boards.
| Pin | Remarks |
|---|---|
| GPIO0 | usually pulled up |
| GPIO1 | UART TxD |
| GPIO2 | usually pulled up |
| GPIO3 | UART RxD |
| GPIO4 | |
| GPIO5 | |
| GPIO6 | Flash SPI |
| GPIO7 | Flash SPI |
| GPIO8 | Flash SPI |
| GPIO9 | Flash SPI in qout and qio mode, see section Flash Modes |
| GPIO10 | Flash SPI in qout and qio mode, see section Flash Modes |
| GPIO11 | Flash SPI |
| GPIO12 | |
| GPIO13 | |
| GPIO14 | |
| GPIO15 | usually pulled down |
| GPIO16 | RTC pin and wake up signal in deep sleep mode |
GPIO0, GPIO2, and GPIO15 are bootstrapping pins which are used to boot ESP8266 in different modes:
| GPIO0 | GPIO2 | GPIO15 (MTDO) | Mode |
|---|---|---|---|
| 1 | X | X | boot in SDIO mode to start OCD |
| 0 | 0 | 1 | boot in UART mode for flashing the firmware |
| 0 | 1 | 1 | boot in FLASH mode to boot the firmware from flash (default mode) |
ESP8266 has one dedicated ADC pin with a resolution of 10 bits. This ADC pin can measure voltages in the range of 0 V ... 1.1 V.
ESP8266 has two SPI controllers:
Thus, HSPI is the only SPI interface that is available for peripherals. It is exposed as RIOT's SPI_DEV(0). The pin configuration of the HSPI interface is fixed as shown in following table.
| Signal | Pin |
|---|---|
| SPI0_MISO | GPIO12 |
| SPI0_MOSI | GPIO13 |
| SPI0_SCK | GPIO14 |
| SPI0_CS0 | GPIOn with n = 0, 2, 4, 5, 15, 16 (additionally 9, 10 in DOUT flash mode) |
The only pin definition that can be overridden by an application-specific board configuration is the CS signal defined by SPI0_CS0.
When the SPI is enabled using module periph_spi, these GPIOs cannot be used for any other purpose. GPIOs 0, 2, 4, 5, 15, and 16 can be used as CS signal. In dio and dout flash modes (see section Flash Modes), GPIOs 9 and 10 can also be used as CS signal.
Since the ESP8266 does not or only partially support the I2C in hardware, I2C interfaces are realized as bit-banging protocol in software. The maximum usable bus speed is therefore I2C_SPEED_FAST_PLUS. The maximum number of buses that can be defined is 2, I2C_DEV(0) and I2C_DEV(1).
GPIO pins (I2C0_SCL, I2C0_SDA and/or I2C1_SCL, I2C1_SDA) have to be defined in the board-specific peripheral configuration in $BOARD/periph_conf.h. Furthermore, the default I2C bus speed (I2C0_SPEED and/or I2C1_SPEED) that is used for I2C bus(ses) has to be defined. The number of configured buses I2C_NUMOF is then determined automatically from these definitions.
In the following example, only one I2C bus is defined:
A configuration with two I2C buses would look like the following:
All these configurations can be overridden by an application-specific board configuration.
The hardware implementation of ESP8266 PWM supports only frequencies as power of two. Therefore, a software implementation of one PWM device (PWM_DEV(0)) with up to 8 PWM channels (PWM_CHANNEL_NUM_MAX) is used.
The GPIOs that can be used as channels of the PWM device PWM_DEV(0) are defined by PWM0_GPIOS. By default, all GPIOs that are not used as I2C, SPI, or UART signals are defined as PWM channels in board definition. As long as these channels are not initialized with function pwm_init, they can be used as normal GPIOs for other purposes. Even if they are already initialized, but have a duty cycle value of 0 can be used as output GPIOs for other purposes. GPIOs in PWM0_GPIOS that are used for other purposes, e.g., I2C or SPI, are no longer available as PWM channels.
To define other GPIOs as PWM channels, just overwrite the definition of PWM0_GPIOS in an application-specific board configuration
There are two timer implementations:
By default, the hardware timer implementation is used.
Software timers use SDK's timers to implement the timer device and the channels. Although these SDK timers usually have a precision of a few microseconds, they can deviate up to 500 microseconds. So if you need a timer with high accuracy, you'll need to use the hardware timer with only one timer channel.
If SPIFFS module is enabled (USEMODULE += esp_spiffs), the implemented MTD system drive mtd0 for the on-board SPI flash memory is used together with modules spiffs and vfs to realize a persistent file system.
For this purpose, the flash memory is formatted as SPIFFS starting at the address 0x80000 (512 kByte) on first boot. All sectors up to the last 5 sectors of the flash memory are then used for the file system. With a fixed sector size of 4096 bytes, the top address of the SPIFF is flash_size - 5 * 4096, e.g., 0xfb000 for a flash memory of 1 MByte. The size of the SPIFF then results from:
Please refer file $RIOTBASE/tests/unittests/test-spiffs/tests-spiffs.c for more information on how to use SPIFFS and VFS together with a MTD device mtd0 alias MTD_0.
The ESP8266 port of RIOT also supports
RTC is not yet implemented.
ESP8266 provides different built-in possibilities to realize network devices:
The RIOT port for ESP8266 implements in module esp_wifi a netdev driver for the built-in WiFi interface.
esp_wifi is not automatically enabled when module netdev_default is used. Instead, if necessary, the application has to add the module esp_wifi in the Makefile.Furthermore, the following configuration parameters have to be defined:
| Parameter | Default | Description |
|---|---|---|
| ESP_WIFI_SSID | "RIOT_AP" | SSID of the AP to be used. |
| ESP_WIFI_PASS | - | Passphrase used for the AP as clear text (max. 64 chars). |
| ESP_WIFI_STACKSIZE | THREAD_STACKSIZE_DEFAULT | Stack size used for the WiFi netdev driver thread. |
These configuration parameter definitions, as well as enabling the esp_wifi module, can be done either in the makefile of the project or at make command line, e.g.:
esp_wifi is not enabled automatically when module netdev_default is used.esp_wifi) and the ESP-NOW network interface (module esp_now) can be used simultaneously, for example, to realize a border router for a mesh network which uses ESP-NOW. In this case the ESP-NOW interface must use the same channel as the AP of the infrastructure WiFi network. All ESP-NOW nodes must therefore be compiled with the channel of the AP asvalue for the parameter 'ESP_NOW_CHANNEL'.The RIOT port for the ESP8266 supports a netdev interface for the ESP32 WiFi SoftAP mode. Module esp_wifi_ap has to be enabled to use it.
The following parameters can be configured:
| Parameter | Default | Description |
|---|---|---|
| ESP_WIFI_SSID | "RIOT_AP" | Static SSID definition for the SoftAP |
| ESP_WIFI_AP_PREFIX | "RIOT_AP_" | Optional prefix for dynamic SSID, if used, the node will create the SSID based on the prefix + mac address (e.g.: "RIOT_AP_aabbccddeeff"). This is disabled by default and ESP_WIFI_SSID is used, define this to enable the usage of the SSID prefix. |
| ESP_WIFI_PASS | none | The password for the WiFi SoftAP network interface. If no password is provided, the interface will be "open", otherwise it uses WPA2-PSK authentication mode. |
| ESP_WIFI_SSID_HIDDEN | 0 | Whether the SoftAP SSID should be hidden. |
| ESP_WIFI_MAX_CONN | 4 | The maximum number of connections for the SoftAP. |
| ESP_WIFI_BEACON_INTERVAL | 100 | The beacon interval time in milliseconds for the SoftAP. |
| ESP_WIFI_STACKSIZE | THREAD_STACKSIZE_DEFAULT | Stack size used for the WiFi netdev driver thread. |
These configuration parameter definitions, as well as enabling the esp_wifi_ap module, can be done either in the makefile of the project or at make command line, for example:
esp_wifi_ap module is not used by default when netdev_default is used.With ESP-NOW, the ESP8266 provides a connectionless communication technology, featuring short packet transmission. It applies the IEEE802.11 Action Vendor frame technology, along with the IE function developed by Espressif, and CCMP encryption technology, realizing a secure, connectionless communication solution.
The RIOT port for ESP8266 implements in module esp_now a netdev driver which uses ESP-NOW to provide a link layer interface to a meshed network of ESP8266 nodes. In this network, each node can send short packets with up to 250 data bytes to all other nodes that are visible in its range.
esp_now is not enabled automatically if the netdev_default module is used. Instead, the application has to add the esp_now module in its makefile when needed.For ESP-NOW, ESP8266 nodes are used in WiFi SoftAP + Station mode to advertise their SSID and become visible to other ESP8266 nodes. The SSID of an ESP8266 node is the concatenation of the prefix RIOT_ESP_ with the MAC address of its SoftAP WiFi interface. The driver periodically scans all visible ESP8266 nodes.
The following parameters are defined for ESP-NOW nodes. These parameters can be overridden by application-specific board configurations.
| Parameter | Default | Description |
|---|---|---|
| ESP_NOW_SCAN_PERIOD | 10000000UL | Defines the period in us at which an node scans for other nodes in its range. The default period is 10 s. |
| ESP_NOW_SOFT_AP_PASS | "ThisistheRIOTporttoESP" | Defines the passphrase as clear text (max. 64 chars) that is used for the SoftAP interface of ESP-NOW nodes. It has to be same for all nodes in one network. |
| ESP_NOW_CHANNEL | 6 | Defines the channel that is used as the broadcast medium by all nodes together. |
| ESP_NOW_KEY | NULL | Defines a key that is used for encrypted communication between nodes. If it is NULL, encryption is disabled. The key has to be of type uint8_t[16] and has to be exactly 16 bytes long. |
esp_now) and the Wifi network interface (module esp_wifi) can be used simultaneously, for example, to realize a border router for a mesh network which uses ESP-NOW. In this case the ESP-NOW interface must use the same channel as the AP of the infrastructure WiFi network. All ESP-NOW nodes must therefore be compiled with the channel of the AP asvalue for the parameter 'ESP_NOW_CHANNEL'.The ESP8266 port of RIOT has been tested with several common external devices that can be connected to ESP8266 boards and are preconfigured accordingly.
RIOT provides a number of driver modules for different types of network devices, e.g., IEEE 802.15.4 radio modules and Ethernet modules. The RIOT port for ESP8266 has been tested with the following network devices:
To use MRF24J40 based IEEE 802.15.4 modules as network device, the mrf24j40 driver module has to be added to the makefile of the application:
The mrf24j40 driver module uses the following preconfigured interface parameters for ESP8266 boards:
| Parameter | Default | Remarks |
|---|---|---|
| MRF24J40_PARAM_SPI | SPI_DEV(0) | fixed, see section SPI Interfaces |
| MRF24J40_PARAM_SPI_CLK | SPI_CLK_1MHZ | fixed |
| MRF24J40_PARAM_CS | GPIO16 | can be overridden |
| MRF24J40_PARAM_INT | GPIO0 | can be overridden |
| MRF24J40_PARAM_RESET | GPIO2 | can be overridden |
The GPIOs in this configuration can be overridden by application-specific board configurations.
To use ENC28J60 Ethernet modules as network device, the enc28j60 driver module has to be added to the makefile of the application:
The enc28j60 driver module uses the following preconfigured interface parameters for ESP8266 boards:
| Parameter | Default | Remarks |
|---|---|---|
| ENC28J60_PARAM_SPI | SPI_DEV(0) | fixed, see section SPI Interfaces |
| ENC28J60_PARAM_CS | GPIO4 | can be overridden |
| ENC28J60_PARAM_INT | GPIO9 | can be overridden |
| ENC28J60_PARAM_RESET | GPIO10 | can be overridden |
The GPIOs in this configuration can be overridden by application-specific board configurations.
ESP8266 port of RIOT is preconfigured for RIOT applications that use the SPI SD-Card driver. To use SPI SD-Card driver, the sdcard_spi module has to be added to a makefile:
The sdcard_spi driver module uses the following preconfigured interface parameters for ESP8266 boards:
| Parameter | Default | Remarks |
|---|---|---|
| SDCARD_SPI_PARAM_SPI | SPI_DEV(0) | fix, see section SPI Interfaces |
| SDCARD_SPI_PARAM_CS | SPI0_CS0 | can be overridden |
The GPIO used as CS signal can be overridden by application-specific board configurations.
The board-specific configuration files board.h and periph_conf.h as well as the driver parameter configuration files <driver>_params.h define the default configurations for peripherals and device driver modules. These are, for example, the GPIOs used, bus interfaces used or available bus speeds. Because there are many possible configurations and many different application requirements, these default configurations are usually only a compromise between different requirements.
Therefore, it is often necessary to change some of these default configurations for individual applications. For example, while many PWM channels are needed in one application, another application does not need PWM channels, but many ADC channels.
To override default board configurations, simply create an application-specific board configuration file $APPDIR/board.h in the source directory $APPDIR of the application and add the definitions to be overridden. To force the preprocessor to include board's original board.h after that, add the include_next preprocessor directive as the last line.
For example to override the default definition of the GPIOs that are used as PWM channels, the application-specific board configuration file $APPDIR/board.h could look like the following:
It is important to ensure that the application-specific board configuration $APPDIR/board.h is included first. Insert the following line as the first line to the application makefile $APPDIR/Makefile.
Using the approach for overriding board configurations, the parameters of drivers that are typically defined in drivers/<device>/include/<device>_params.h can be overridden. For that purpose just create an application-specific driver parameter file $APPDIR/<device>_params.h in the source directory $APPDIR of the application and add the definitions to be overridden. To force the preprocessor to include driver's original <device>_params.h after that, add the include_next preprocessor directive as the last line.
For example, to override a GPIO used for LIS3DH sensor, the application-specific driver parameter file $APPDIR/<device>_params.h could look like the following:
It is important to ensure that the application-specific driver parameter file $APPDIR/<device>_params.h is included first. Insert the following line as the first line to the application makefile $APPDIR/Makefile.
Please note:** To make such application-specific board configurations dependent on the ESP8266 MCU or a particular ESP8266 board, you should always enclose these definitions in the following constructs:
ESP8266 RTOS SDK libraries create a number of high-priority threads, see the listing below, which handle high priority interrupts from SoC and WiFi hardware. These threads are also created, if the WiFi hardware is not used.
Using module esp_idf_heap enables the compilation of SDK heap handling instead of memory management provided by newlibc.
Normally, the remaining ESP8266 DRAM, which is not used by static variables, is provided as heap memory. The SDK heap implementation also provides the unused ESP8266 IRAM (Command RAM) as the additional heap memory region.
The following example shows the heap when the esp_idf_heap is used:
In this example, heap region 0 at address 0x401xxxxx is located in IRAM and heap region 1 at address 0x3fffxxxx in DRAM. While memory management functions of newlibc use always heap region 1 in DRAM, functions of binary SDK libraries like the WiFi stack can also also heap region 0 for 32-bit aligned data.
There are two options to debug your RIOT application for ESP8266 either
QEMU and module esp_gdb, see QEMU Mode andB oresp_gdbstub, see Module esp_gdbstub.When QEMU mode is enabled by using the esp_qemu module, make flash does not try to download the image of your RIOT application to the target hardware. Instead, a binary image $ELFFILE.bin as well as the 1 MByte flash image esp8266flash.bin is created in the application build directory . This flash image can be used together with QEMU and GDB to debug the application.
For debugging purposes, the application should be compiled with debugging information. This can either be done by using the esp_gdb module, for example:
To use QEMU, you have to install QEMU for Xtensa with ESP8266 machine implementation first as following.
Once the compilation has been finished, QEMU for Xtensa with ESP8266 machine implementation should be available in /path/to/esp/qemu/bin and you can start it in first terminal with
where /path/to/build/dir is the path to the application build directory where $ELFFILE.bin is generated by the make command, for example /tests/shell/bin/esp8266-esp-12x. After that you can start GDB in second terminal window using command:
To start debugging, you have to connect to QEMU from GDB with command:
QEMU does not support the emulation of hardware interrupts or special hardware modules like the WiFi module. Applications that rely on interrupts or the WiFi interface can only be debugged with restrictions with QEMU and GDB.Using the esp_gdbstub module enables the compilation of the gdbstub interface for ESP8266. This interface implements the target side of the GDB Remote Protocol. The initial gdbstub implementation for ESP8266 was provided by Espressif. However, for using it with RIOT it had to be changed a lot.
gdbstub interface automatically enables the compilation with debug information (module esp_gdb) gdbstub.To start debugging, the application has to be compiled using module esp_gdbstub, for example:
Once, the application is flashed to ESP82666, debugging can be started as following.
where <port> is the serial interface to which the ESP8266 module is connected, e.g., /dev/ttyUSB0.
where /path/to/build/dir is the path to the application build directory where $ELFFILE.bin is generated by the make command, for example /tests/shell/bin/esp8266-esp-12x.
GDB to the ESP8266 module with command: where <port> is the serial interface to which the ESP8266 module is connected, e.g., /dev/ttyUSB0.
By default, gdbstub stops the execution automatically using function gdbstub_do_break after the board initialization and before the kernel is initialized.
At this time, you can set breakpoints, execute the application stepwise or just continue the execution using the continue command. Please note the limitations below. Once you have started the execution in GDB, you can use Ctrl-C in GDB or the console window to break it anytime.
If your application uses console inputs (stdio), such as the tests/shell application, you can type characters in the console window that gdbstub will forward to the application. However, the echo of these inputs occur in GDB.
GDB are using the same serial port, typed characters can be lost sporadically.When you reset the ESP8266 module, you will observe a message such as the following after boot messages in the console window.
This is simply the first GDB Remote Protocol packet that is generated as a result of the automatic break during the initialization when the GDB is not yet connected to the ESP8266 module.
Due to hardware limitations of the Xtensa architecture, esp_gdbstub debugging has the following limitations:
br) only work for code in IRAM with addresses 0x4010xxxx, see below.0x402xxxxx require a hardware breakpoint (command hbr), see below.hbr).watch).0x4010xxxx, see below.If you want to use multiple software breakpoints or execute stepwise on source code level, you have to ensure that the function you want to debug is located in RAM. For that purpose, add the IRAM attribute to that function, for example:
Then you should be able to set a breakpoint to this function using command bp and to execute it stepwise after break.
Another option is to use gdbstub_do_break() wherever you want to break the execution. If you know where you want to break before downloading the program to the target, you can use gdbstub_do_break() as much as you want.
Modules | |
| ESP-NOW netdev interface | |
| WiFi based ESP-NOW network device driver. | |
| ESP-WiFi netdev interface | |
| Network device driver for the ESP SoC WiFi interface. | |
| ESP8266 SDK interface | |
| Function declarations and mappings for compatibility with ESP8266 SDK. | |
| ESP8266 compile configurations | |
| Compile-time configuration macros for ESP8266 modules. | |
Files | |
| file | gpio_arch.h |
| Architecture specific GPIO functions for ESP8266. | |
| file | irq_arch.h |
| Implementation of the kernels irq interface. | |
| file | periph_cpu.h |
| CPU specific definitions and functions for peripheral handling. | |
| file | sdk_conf.h |
| SDK configuration compatible to the ESP-IDF. | |
| file | syscalls.h |
| Implementation of required system calls. | |
1.8.17