STM32F0 SPI Slave wrong behaviour

[sebastien23]

Posted on January 08, 2016 at 15:28

Hi

I'm stuck in my project by this spi problem. What i do is simple, i send a data from a stm32f0 (master) to another one (slave) but here is the problem: while i see on the scope the good frame, the slave device doesn't. More precisely, it sees the data divided by 2. Plus i have to send the data twice to make the slave device understand something other  than 0x00.. In the case of the slave, i handle the communication by interrupt whereas the reference manual says that it is preferable to use DMA. Do anybody found this problem someday?? I really need to work this out

[re.wolff9]

Posted on January 09, 2016 at 20:42

I suspect that you have a ''mode'' problem. There are 4 modes with SPI, specifying the clock polarity and resting state. If you get things wrong, the slave will recieve dat one bit-clock a too late and give you data that  you call ''divided by two''. 

[sebastien23]

Posted on January 11, 2016 at 09:53

But i've already check  the CPOL and CPHA, they are the same for master and slave. I've also tried to change them but still the same problem..

[sebastien23]

Posted on January 12, 2016 at 16:35 Finally i got it working perfectly well with DMA..