qmk/qmk_firmware
1
0
Fork 0
mirror of https://github.com/qmk/qmk_firmware.git synced 2026-10-01 22:40:11 +02:00
Code Issues Packages Projects Releases Wiki Activity

Upstream merge up to 02d44beb44

Browse Source
This commit is contained in:
jonathan.liu
2019-07-11 23:21:18 -07:00
parent a0fac849eb
commit 441b212c86
4854 changed files with 157570 additions and 41535 deletions
Download Patch File Download Diff File Expand all files Collapse all files
docs/i2c_driver.md
+12 -8
View File
@@ -12,7 +12,7 @@ The I2C Master drivers used in QMK have a set of common functions to allow porta
|`uint8_t i2c_receive(uint8_t address, uint8_t* data, uint16_t length, uint16_t timeout);` |Receive data over I2C. Address is the 7-bit slave address without the direction. Saves number of bytes specified by `length` in `data` array. Returns status of transaction. |
|`uint8_t i2c_writeReg(uint8_t devaddr, uint8_t regaddr, uint8_t* data, uint16_t length, uint16_t timeout);` |Same as the `i2c_transmit` function but `regaddr` sets where in the slave the data will be written. |
|`uint8_t i2c_readReg(uint8_t devaddr, uint8_t regaddr, uint8_t* data, uint16_t length, uint16_t timeout);` |Same as the `i2c_receive` function but `regaddr` sets from where in the slave the data will be read. |
|`uint8_t i2c_stop(uint16_t timeout);` |Stops the I2C driver. |
|`uint8_t i2c_stop(void);` |Ends an I2C transaction. |
### Function Return
@@ -33,8 +33,8 @@ The following defines can be used to configure the I2C master driver.
|Variable |Description |Default|
|------------------|---------------------------------------------------|-------|
|`#F_SCL` |Clock frequency in Hz |400KHz |
|`#Prescaler` |Divides master clock to aid in I2C clock selection |1 |
|`F_SCL` |Clock frequency in Hz |400KHz |
|`Prescaler` |Divides master clock to aid in I2C clock selection |1 |
AVRs usually have set GPIO which turn into I2C pins, therefore no further configuration is required.
@@ -63,20 +63,24 @@ Lastly, we need to assign the correct GPIO pins depending on the I2C hardware dr
By default the I2C1 hardware driver is assumed to be used. If another hardware driver is used, `#define I2C_DRIVER I2CDX` should be added to the `config.h` file with X being the number of hardware driver used. For example is I2C3 is enabled, the `config.h` file should contain `#define I2C_DRIVER I2CD3`. This aligns the QMK I2C driver with the Chibios I2C driver.
STM32 MCUs allows a variety of pins to be configured as I2C pins depending on the hardware driver used. By default B6 and B7 are set to I2C.
STM32 MCUs allows a variety of pins to be configured as I2C pins depending on the hardware driver used. By default B6 and B7 are set to I2C. You can use these defines to set your i2c pins:
This can be changed by declaring the `i2c_init` function which intentionally has a weak attribute. Please consult the datasheet of your MCU for the available GPIO configurations. The following is an example initialization function:
| Variable | Description | Default |
|-------------|----------------------------------------------|---------|
| `I2C1_BANK` | The bank of pins (`GPIOA`, `GPIOB`, `GPIOC`) | `GPIOB` |
| `I2C1_SCL` | The pin number for the SCL pin (0-9) | `6` |
| `I2C1_SDA` | The pin number for the SDA pin (0-9) | `7` |
You can also overload the `void i2c_init(void)` function, which has a weak attribute. If you do this the configuration variables above will not be used. Please consult the datasheet of your MCU for the available GPIO configurations. The following is an example initialization function:
```C
void i2c_init(void)
{
setPinInput(B6); // Try releasing special pins for a short time
setPinInput(B7);
chThdSleepMilliseconds(10); // Wait for the release to happen
wait_ms(10); // Wait for the release to happen
palSetPadMode(GPIOB, 6, PAL_MODE_ALTERNATE(4) | PAL_STM32_OTYPE_OPENDRAIN | PAL_STM32_PUPDR_PULLUP); // Set B6 to I2C function
palSetPadMode(GPIOB, 7, PAL_MODE_ALTERNATE(4) | PAL_STM32_OTYPE_OPENDRAIN | PAL_STM32_PUPDR_PULLUP); // Set B7 to I2C function
}
```