cancel
Showing results for 
Search instead for 
Did you mean: 

SPI communication between two STM32 Discovery

edxxgardo
Associate II
Posted on March 31, 2011 at 11:13

SPI communication between two STM32 Discovery

5 REPLIES 5
Andrew Neil
Evangelist III
Posted on May 17, 2011 at 14:30

''I connected the Master GPIO pins 5,6,7 to the Slave GPIO 13,14,15''

 

Pin numbers are pretty meaningless  - what are the pin functions?

''Master seems to work because I can monitor it via the interrupt''

You haven't shown your interrupt handler, so it's impossible to know if that's a valid or meaningful test.

Anyhow, it tells you nothing about what's actually happening on the physical connection betwen the two boards.

Have you looked with an oscilloscope?

edxxgardo
Associate II
Posted on May 17, 2011 at 14:30

PA 5(SCK),6 (MISO),7(MOSI) from Master side

PB 13(SCK),14(MISO),15(MOSI) from Slave side.

You are right ...using the osciloscope is a good way to test it. I mentioned that apparently from the Master it works, but what works is just the triggering of the interrupt and the sending out the bytes. There is a buffer with a bunch of bytes and one by one are collected by the IRQ and I see it from the debugger:

void Slave_Buffer(void)

{

    /* Store SPI_SLAVE received data */

    Slave_Buffer[buffer_Index++] = SPI_I2S_ReceiveData(SPI_SLAVE);

}

this function is called from the IRQ in the Slave.

I'm going to check using the osciloscope, but in the mean time I wanted to know from somebody in the forum wether there is something wrong in the code. There are so many parameters in the setting that, even if I used the osciloscope, I can spend hours in trying one by one these parameters, then recompile, download, ecc.

Thanks anyway for the supprot,

regards,

Posted on May 17, 2011 at 14:30

With two separate devices both could use SPI1?

It's never made a whole lot of sense to me to have ALL the pins as AF_PP, but all the examples look that way.
Tips, Buy me a coffee, or three.. PayPal Venmo
Up vote any posts that you find helpful, it shows what's working..
Andrew Neil
Evangelist III
Posted on May 17, 2011 at 14:30

''PA 5(SCK),6 (MISO),7(MOSI) from Master side

 

PB 13(SCK),14(MISO),15(MOSI) from Slave side''

But how are they connected? What connects to what?

You're not using a Slave Select line...?

Posted on May 17, 2011 at 14:30

But how are they connected? What connects to what?

Probably one-to-one, which should work for full duplex modes, but the 1 line Tx/Rx modes it documented as :

 - Connect SPI2 SCK pin (PB.13) to SPI1 SCK pin (PA.05)

 - Connect SPI2 MISO pin (PB.14) to SPI1 MOSI pin (PA.07)

When cut-n-pasting example code, it always helps to read the README.TXT file.

Tips, Buy me a coffee, or three.. PayPal Venmo
Up vote any posts that you find helpful, it shows what's working..