Use I2S_CKIN external clock source for SPI?

[Rhodes.Ethan]

Posted on April 04, 2018 at 17:08

Is it possible to use the I2S_CKIN external clock source for SPI rather than come off the peripheral clock? From the reference manual it appears that this external clock is available as a source only when the SPI is in 'I2S Mode'. Is there a workaround? I am using an STM32F765. Thanks!

#i2s_ckin #spi

[Tesla DeLorean]

Posted on April 04, 2018 at 17:30

>>

it appears that this external clock is available as a source only when the SPI is in 'I2S Mode'

OR an SPI Slave

[Rhodes.Ethan]

Posted on April 04, 2018 at 17:50

Yes, that makes sense. Looking a little more closely at the reference manual, it looks pretty clear that an SPI Master clock can only be sourced from PCLK2 with a divider that is configured through the BR[2:0] bits in the SPIx_CR1 register. The I2SSRC bit in the RCC_CFGR register is stated to configure the source for I2S only.