I'm trying to debug a board with SN75LVDS83 and a DM368, comparing the output waveforms of the LVDS83 and another, known working, LVDS source feed with the same data at the same time.
I've uploaded schematics and output waveforms on imgur, I hope that is fine.
This is the schematics:
Data line 1, yellow is the working LVDS interface, blue the one I'm debugging:
Always data line 1, zoomed in:
Data line 2, yellow is the working LVDS interface, blue the one I'm debugging:
Data line 3, yellow is the working LVDS interface, blue the one I'm debugging:
Always data line 3, zoomed out:
Clock, yellow is the working LVDS interface, blue the one I'm debugging:
As you can see from data 1 HSYNC/VSYNC seems to be working (the output is 1280x800@60fps). The same or similar data seems to be encoded in both LVDS chips, but the working one spends more time oscillating around the top of the waveform, I don't know if the output is binary and the working LVDS IC simply works that way, with a bigger ripple.
I find it difficult to explain LVDS line 2, apart that there doesn't seem to be the 16ms frame length visible, or maybe it is, it is just almost invisible. Line 3, that also doesn't seem right. About the clock, it oscillating that way, I can't explain it either but I would like to believe it is supposed to work that way, since that when disconnecting the LVDS IC I'm debugging and leaving only the working LVDS IC the behaviour remained unchanged.
I would really appreciate any help on what to look at next to understand what I did wrong.
Thank you,
Giovanni
