Respected Mentors and my fellow Students
The progress that I have made in the last week is as follows:
1)I wrote and compiled the basic SPI module with all the four clock phases and polarity.
- With my mentors help,I wrote a makefile to compile the above code.This can be seen here:https://github.com/chanakya-vc/PRU-I2C_SPI_master/tree/wip_on_spi
1)Unfortunately for the code to be loaded on the PRU,an empty resource table has to present in the code.So I was unable to load the code on the PRU.This can be found here and I will include this in my code:http://git.ti.com/pru-software-support-package/pru-software-support-package/blobs/master/examples/am335x
2)The other problem was to configure pins to behave as the input/output pins via a dt.Fortunately I was told about a method called config-pin by my mentors. And I am going to be using this for testing purposes.Reference: http://paste.debian.net/723608/
- For loading the codes I am following this:https://gist.github.com/alexanderhiam/2c4187c710b2c409d8dde8c4015fe007
1)Finish this particular framework by the end of this week.Test it on the PRU and record the waveforms on a logic analyzer.
2)The biggest problem that I am facing is that I am unable to figure out a way to get the PRU to access the shared DDR memory. Other than RPMsg(which doesnot seem to be the best choice as of now),I can’t think of any approach.There was a procedure for upcalls and downcalls in the earlier kernels but this doesn’t seem to be the case any more.