PDP-8/E Omnibus unexpected behavior

[AK6DN]

The PDP-8efm Maintenance Manual volume 1 pp 3-96 thru 3-106 has a very detailed description of how the programmer's console logic operates.

 

[BitWiz]

I figured as much and TP4 is the obvious place to latch the address if you are a memory board. Clearly not quite what he was looking for here. Looking forward to hearing if SOURCE does what he wanted. It still wont latch on the Load Addr switch press which probably means it still won't be exactly what is wanted.

As long as the the address latched is the address of the data represented on the MB lights I will be happy. It doesn't have to be when ADDR LOAD is pressed but can be after DEPOSIT or EXAM is pressed.

Thank you.

 

[BitWiz]

The address information is permanent on the bus. So you just need a driver for the LED, you don't need to latch anything.

The latch is specifically to handle the fact that the address is the next address not the current address and to handle any transitions on the bus that don't need to be displayed.