Hi,
some update. I received my pcb order to have the connector available outside to play with this saturday.
I just tried to use the serial port of my TDS3000(A) but with no success.
Seem like the A model, we must use the hardware RTS/CTS control flow (don't have anything to test against for the moment) or the serial port is disabled by default (fuxxored).
I would more easyli go for the second idea as there is nothing about a serial port in the menus (my 3032C has serial port config event without an extension card).
So getting a Floppy emulator to downgrade the firmware seem now less urgent
BTW for the screen as it's connected "directly" to the lcd connector the signal is present as soon as the scope is on.
pin 2, 11: DotClock 25MHz
pin 3 : HSync 31.5Khz (lonw 31,72us)
pin 4 : VSync 60,16Khz (low 16,62ms)
Pin 6-9 : Red [0-3]
Pin 51,52,54,55 : Green [0-3]
Pin 56,57,59,60 : Blue [0-3]
I have mapped the datalines and some of the address lines too but for the moment i can't confirm their axact assignation(just some guess).
After some more playing i think like james_s that some pins are used to detect the type of extension card. But it seem more tricky than some lines to ground.
I have a bunch of pins that have no signal on them :
High state : 13, 15, 24, 65, 66
Low state : 14, 16, 18, 19, 20, 22, 23, 25, 61, 62, 63, 64
Given the position of the pins i suspect the LC00A and LC08A to have something to to with the identification of the module.
They're probably only for the logic to enable/disable the 245's of the GPIB controller, but it can be a possibility that one of thoses is used to act as a "ROM" on the data bus for a byte to identify the module.
Edited to add pins 61 to 64.