SPI programming through PRU on AM57xx

Rakesh Modi

Hello,

I have connected a DAC on mcspi4 of AM57xx. I want to communicate with DAC through PRU using SPI. So is there anyway that PRU can communicate with this DAC directly? Or it can be possible only through bit-banging?

Any example for PRU SPI will be great help.

over 9 years ago

0 Biser Gatchev-XID over 9 years ago

TI__Guru**** 393215 points

Hi,

There is no SPI peripheral inside the PRU cores, however you can access the McSPI peripheral directly from the PRU. If you want direct communication with the DAC, you will need to write a software SPI for the PRU.

0 Rakesh Modi over 9 years ago in reply to Biser Gatchev-XID

Expert 1680 points

I have seen that constant table of AM57xx and there is no mcspi device address, so It looks like I can access the MCSPI through PRU, so i would prefer to use shift register.

0 Rakesh Modi over 9 years ago in reply to Biser Gatchev-XID

Expert 1680 points

Hello Biser,
Could you please provide me any example code to access mcspi through PRU on AM57. Should I have to write registers of mcspi directly from PRU? Do I have to do anything else? Please note that MCSPI is also enabled in ARM kernel, so in that case how can I access MCSPI from PRU?

0 Biser Gatchev-XID over 9 years ago in reply to Rakesh Modi

TI__Guru**** 393215 points

Yes, SPI registers can be directly accessed from the PRU. I am not sure however what will happen if the SPI is already enabled in the Linux kernel. It could be locked for access from other sources.

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SPI programming through PRU on AM57xx