I am having trouble receiving data with my Riverdi Display rvt70hssfwca0. I am not sure if it is a software or a hardware problem since when I was testing the RS485 I shorted pin 2 (Signal A - Non inverting) and Pin 1 (Vin - 24V). When debugging this is what I observed.
- Signal coming from Pin 2 of RS485 port is little over 1V instead of 3.3V while Pin 3 (Signal B -Inverting) is working fine at 3.3V.
- When the device connected to the RS485 port replies back both signals (A and B) are at 3.3V.
- I believe D4 might be damaged because I could see a physical discrepancy on the casing (a little hole).
- At U2 the incoming signal and the outputting signals seem similar to what was observed at the RS485 connector port. (Outgoing A is ~1V, everything else is 3.3V)
- This is where I find the main suspect:
- The receiving signal observed from RO pin (going back to the MCU I suppose) are pulse-like (noise maybe) instead of the expected squared IO signal observed at the port. In other words, the DC voltage becomes low, 0V, and where there are supposed to be a signal 1 (3.3V square pulse) see a peak (Pulse).
I suspect either D4 or U2 damage might be blocking the signal somehow from going back to the MCU. But there is a possibility that I need to enable something in the MCU using software to disable high impedance, maybe? - Which I did, by setting PA15 low, right? I checked the DE and RE pins on U2 and the seem to set themselves on and off correctly at the same time when the display is outputting a signal. They are both on when transmitting, and off every other time.
I also looked into the rvt70hssfwca0 schematic but I could not find it. U2 is a (I believe) ST3485EBDR interface IC. I do not know what D4 is, yet.
Any help works!
