thmalmeida / stm32fx

i2c_to_gpio using STM32F103C8T6

GPIO extender over I2C protocol

This project has the main propose to work as gpio expander over I2C protocol. It uses the mcu STM32F103C8T6 with cortex-M3. Here, we have the make file to build, flash e monitor the project.

Dependencies

• st link to flash, debug and traceswo

Follow the link: https://github.com/stlink-org/stlink

apt install stlink-tools gdb-multiarch openocd

Install arm-none-eabi compiler available on ARM oficial site.

Go to session x86_64 Linux hosted cross toolchains and choose AArch32 bare-metal target (arm-none-eabi)

Debugger test with OpenOCD and gdb

Test the openocd and st-link V2 with the following command:

$  openocd -f interface/stlink.cfg -f target/stm32f1x.cfg

Run the gdb

$ gdb-multiarch build/filename.elf

And type

(gdb) target extended-remote localhost:3333

OpenOCD debugger xpm (not used. Skip it!) 20230124

Follow the instructions into https://github.com/xpack-dev-tools/openocd

Install the latest xpm (https://xpack.github.io/xpm/install/)

sudo npm install --global xpm@latest

install xpack-dev-tools https://xpack.github.io/openocd/install/ https://www.npmjs.com/package/@xpack-dev-tools/openocd for eclipse use

xpm install --global @xpack-dev-tools/openocd@latest --verbose

or uninstall

xpm uninstall --global @xpack-dev-tools/openocd --verbose

sudo npm uninstall --global xpm

arm-gnu-toolchain-12.2.rel1-x86_64-arm-none-eabi.tar.xz

Get started

First of all you should have one ST-Link V2 and make the properly connection.

ST-Link V2	STM32F103C8T6
+3V3	Vcc pad
GND	GND pad
SWDIO	PA13
SWCLK	PA14
TRACESWO	PB3

$ make
$ make flash
$ make monitor

I2C parameters

The device works on I2C slave mode and has the following parameters

Device address: 0x23
Frequency: 400 kHz

Operation codes like as PCF8575

0b 0000 0000

| set pin | | 0x03

| reset pin | | 0x reset pin

I2C commands

• probe
• soft reset
• config
• put
• get
• get temperature
• uptime
• reset reason
• Irms (dsp function)
• array data receive

launch.json example

{ "version": "0.2.0", "projectName": "i2c_to_gpio", "configurations": [ { "name": "ST-LINK V2 DEBUGGER", "type": "cortex-debug", "request": "launch", "cwd": "${workspaceRoot}", "servertype": "openocd", "executable": "${workspaceFolder}/i2c_to_gpio/build/i2c_to_gpio.elf", "configFiles": [ "interface/stlink.cfg", "target/stm32f1x.cfg" ], // "device": "STM32F103C8T6", "interface": "swd", "runToEntryPoint": "main", // "svdFile": "${workspaceFolder}/i2c_to_gpio/STM32F103.svd", // Include svd to watch device peripherals "preLaunchCommands": [ "set mem inaccessible-by-default off", "monitor reset" ], "postLaunchCommands": [ "monitor reset init", "monitor sleep 200" ] // "swoConfig": // { // "enabled": true, // "cpuFrequency": 72000000, // "swoFrequency": 4000000, // "source": "probe", // "decoders": // [ // { // "label": "ITM port 0 output", // "type": "console", // "port": 0, // "showOnStartup": true, // "encoding": "ascii" // } // ] // } } ] }