[riot-notifications] [RIOT-OS/RIOT] cpu/saml1x: add support for SAML10 and SAML11 MCUs (Cortex-M23) (#10653)

Dylan Laduranty notifications at github.com
Mon Jan 21 14:43:38 CET 2019


dylad commented on this pull request.



> @@ -92,19 +92,6 @@ void i2c_init(i2c_t dev)
 
     /* I2C using CLK GEN 0 */
     sercom_set_gen(bus(dev),i2c_config[dev].gclk_src);
-#if defined(CPU_FAM_SAML21) || defined(CPU_FAM_SAMR30)

This code setup the SERCOM_GCLK_SLOW clock for the SERCOM your are using. (which is completely unrelated to the SERCOM_GCLK)
According to, SAML21 datasheet, the SERCOM_GLCK_SLOW is used for : 
```
Two generic clocks ared used by SERCOM, GCLK_SERCOMx_CORE and 
GCLK_SERCOM_SLOW.
The core clock (GCLK_SERCOMx_CORE) can clock the I 2 C when working as a master. The slow clock
(GCLK_SERCOM_SLOW) is required only for certain functions, e.g. SMBus timing. These clocks must
be configured and enabled in the Generic Clock Controller (GCLK) before using the I 2 C.

```
Those SMBus features can be active in the CTRLA register for each SERCOM. We're not using them in RIOT codebase.

See chapter 34.5.3 of [SAML21 datasheet](http://ww1.microchip.com/downloads/en/DeviceDoc/60001477A.pdf).

The SERCOM_SLOW clock is NOT used by UART nor SPI.

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