Other Parts Discussed in Thread: LP5891,
Tool/software:
I am attempting to interface with the LP5891 (specifically the LP5891EVM) via a custom Linux driver on a modified SSI port (continues clock etc.). It seems I have correctly configured the driver to create the CCSI as specified and I am able to read and write to the LP5891 properly but am not able to get anything to display on the LEDs and am wondering what I am missing.
I am following the example code for the C2000 but that seems to be the only "documentation" that would explain how to properly configure and drive the LP5891EVM
First I set the Chip ID using broadcast which looks correct:
I am configuring FC0-> FC4 as exactly specified in the C2000 example (this is FC0 write):
and am able to confirm that is set via read:
My logic analyzer will not decode the CCSI automatically, but manually confirmation looks good to my eyes (There isn't any documentation on register writes so I'm not sure if I am missing something on bit/byte order).
The register writes look as such (repurposed from FC_settings.h):
FC0: 0xAA 0x00 0x00 0x00 0x71 0xCF 0x01 0x00
FC1: 0xAA 0x01 0x01 0xA5 0xE2 0x52 0x95 0xFF
FC2: 0xAA 0x02 0x00 0x0D 0xD0 0x33 0x00 0x00
FC3: 0xAA 0x03 0x00 0x7A 0x40 0x55 0x8F 0x00
FC4: 0xAA 0x04 0x00 0x07 0x00 0x3F 0x40 0x00
After that I am writing white for all (0xFFFF) to SRAM, followed by a VSYNC command. I would expect from looking through the code that this would turn on all LEDs on the EVM but I am seeing nothing. I do see the current drawn drop for about 12mA to 7mA after the FC registers are written but I am not sure how to debug this further.
Do you have any guidance on how I might provide some minimal work to confirm that the system is operable, i.e. get LEDs on/off?
Do you have any debugging guidelines for the EVM System?
Am I missing any steps in this initial bring-up?
Thanks,
Galen
