I'm having trouble getting the PIC on my FMCOMMS1 to initiate SPI transactions.
I've got a simple software based bit bang i2c going in python.
And so far can read the firmware version info no problems.
I read back:
'AD-FMCOMMS1-EBZ RevB FW003'
I'm now trying to readback some registers from the AD9122.
But so far no luck.
My sequence to read register 0x0 from AD9122 is:
I'm probing the SPI lines on the FMCOMMS1 board and don't see any action.
The final I2C read returns 0x1a, which is wrong.
My SCL speed is ~200Hz, which is pretty slow.
I'm wondering if there's a timeout in the PIC fimrware?
I've been over the I2C waveforms and can't really see anything wrong.
Since I can readback the firmware version, the I2C interface appears to be alive.
I just can't seem to trigger any SPI transactions.
I'm on a VC709, which doesn't have a ref design, so I can't drop back to those to compare the waveforms.
I do have a ML605, so I might dig that out and fire it up as a fallback.
Can anyone provide some more things to try?
Are there any example waveforms available that show how to trigger a SPI transaction?