I have recently acquired an HP 6632A power supply and was inspired by Roberto Barrios' project of replacing the screen with an OLED display to do the same. However, it is evident that the 6632A is much different as it doesn't have a front panel board and separate serial connection. Instead, the LCD driver is controlled directly by the CPU through a latch.
Pg.101 of the service manual
Looking up DFI, ISA, SYNC, INA, etc yielded nothing in combination with LCDs.
I probed up the 16-pin connection according on the schematic, though I could be missing something.
These signals are sent at ~2.5Hz when idling: Here are the rest of my captures
I'm not sure where to go from here. Probe 6 looks like clock (hooked up to pin 12 on the left), yet it stops when data comes in. Probes 4 and 5 appear to be exactly the same, just shifted 5us. I'm not able to get any sort of serial decoding working through Saleae Logic, obviously. I probed the rest of the pins to make sure I wasn't missing any signals (or negative voltage for the LCD). I've tried to compare the enabled segments' binary representation with the signals, but I couldn't make any correlations.
I would appreciate if someone could point me in the right direction. Thanks!