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SPI1 & SPI3 & JTAG

Question asked by pantelis on Apr 17, 2015
Latest reply on Apr 17, 2015 by pantelis
Hello!

I am fairly new to the specific Microcontrollers and of course to this forum, so first of all hello to everyone!

Even though my question might be simple enough for most of you, I would like to express you my thoughts about an issue I am facing and if you could please tell me whether I am correct or I am missing something :D.

I am using for an application the STM32F407 and what I would like to do, is use simultaneously SPIs 1,2 and 3 in order to communicate with 3 external ADCs. However I find some difficulty, while trying to think how I am going to debug this code, since the SS pins of SPIs 1 and 3 are sharing the exact same pins.

What I mean by that, is that SPI1_NSS and SPI3_NSS share their pins with JTDI and one solution would be to remap those 2 to some other pins, however according to the datasheet, the other pin at which we could remap those to is actually the same and it's PA4.

The only solution that I could think of is to control the slave selection using the SSM bit and ignore the NSS pin. Is that correct, or there is also a hardware solution which I am missing?

Thank you in advance for your help!

Regards,
Pantelis

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