SPI over USART2 on STM32L052K8?

[Marco Ferdinandi]

Posted on January 16, 2018 at 12:09

Hi,

I would like to know how to use the USART2 on my board (integrating the STM32L052k8 mcu) to communicate in SPI with an external slave.

Is it possible? How can I do it? Is there an example or a snippet which I can use as starting point?

Finally: my first target is to build a transparent bridge USB - SPI (over the pins PA1 PA2 PA3 PA4). Is there an example or a guideline which I can follow?

Thanks in advance,

Marco

[Tesla DeLorean]

Posted on January 16, 2018 at 17:38

The pin routing does not describe an SPI use case for PA[1..4]

http://www.st.com/content/ccc/resource/technical/document/datasheet/dc/d6/6d/24/86/2a/40/d3/DM00108217.pdf/files/DM00108217.pdf/jcr:content/translations/en.DM00108217.pdf

 

You will need to bit-bang those GPIO pins.

There might be some way to use the USART in a synchronous mode, but you'll need to be able to address the start and stop bits, etc. I would suggest hooking to a logic analyzer and reviewing the signalling you can generate.

[Marco Ferdinandi]

Posted on January 17, 2018 at 16:32

Hi,

thanks for the answer. At this point, is there a software library which implements SPI in software using pins as GPIO for my STM32L052k8 mcu?

Thanks in advance,

Marco

[Tesla DeLorean]

Posted on January 17, 2018 at 16:58

No, it isn't that complicated to implement

[waclawek.jan]

Posted on January 17, 2018 at 18:16

See AN4655.

JW