SPI configured as Master with software SS. Which SPI bits do I need to enable to see the clock on the SCK pin? Image CR1 register.

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The image shows that when SS switches to zero, the SCK clock starts immediately. When I enable SSI on the Master, the clock does not start.

RM0090 Reference Manual Page 883 RM0090 Reference Manual


1 Answer 1


You have misunderstood how SPI works and what you want to do is not possible.

The SPI clock does not start when SS goes low.

The SPI clock only appears on bus when transferring data. So you can't just start a clock unless you are transferring something.


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