BTW, I believe the BeaglePilot project is running those drivers on the PRU, so this is the same as running on the Cortex-A8 bare-metal.
Regards,
John
I’d use Starterware as intended with a real RTOS like TI RTOS
BTW, I believe the BeaglePilot project is running those drivers on the PRU, so this is the same as running on the Cortex-A8 bare-metal.
I’ll take your word on that, as I have not really done much with that git project. Initially, I found it a waste of my time. Perhaps later I’ll revisit it and see what I missed.
But I also initially started learning how to use the ti-cgt PRU C compiler, but without CCS ( I prefer to stay as close to gcc as possible ), and found it rather difficult to proceed passed getting basic stuff working. So, I went back to attempting to “relearn” asm, and in the process learn PASM, and the PRU instruction set. Which of course initially I had a hard time with too, but I’m starting to understand more now.
Now I remember why I gave up on assembly so many years ago . . . the syntax is enough to make anyone “choke” . . .
hello Micka,
in attach you’ll find the archive with both asm and c sources: I’ve translated comments to english in order to make them more readable.
I’ve used https://github.com/beagleboard/am335x_pru_package as develop enviroment.
This example uses 2 I/O expanders (one for inputs and the other for outputs) and simply echoes the inputs to the outputs: the echo is done into the c code (that runs in the ARM core) with data passed to and for the PRU into the RAM.
The PRU manages the I2C1 module for init and refresh the I/O expanders.
Mux setting of I2C pins have to be done before execution.
It can’t be done by the PRU itself because the CONTROL_MODULE can’t be accessed (writing) by the PRU.
So I used cape-universal and a shell script for that.
iic_ioexp.zip (6.63 KB)
What kind of script ?? Can you post that? I would have thought mux-clock is done in a gel file
Thx GianFranco,
I managed to understand your code, which is well made.
My first test was to verify if I was able to compile the program and see if something goes out of the I2C 1.
And yes it works ! I saw something on the scope.
Now, I have to modify your code to be able to use the AD7997.
Thank you very much for your code and the comment !
Micka,
Hi,
William, I don’t get it …
Where do you see that the constant C2 == 0x4802_A000
Ah, ok got it. Page 25 of the PRU reference manual table 9
2 I2C1 0x4802_A000 == base address for i2c1
This link is removed, do you still remember / have the solution?