NF6X
Veteran Member
The thread about controlling Christmas tree lights with a PDP-8 got me thinking about doing general purpose I/O (GPIO) with my PDP-11/44 once I get it up and running. Being able to control a bank of relays would be quite useful. Having general purpose digital and/or analog I/O would also be cool. So, I wonder what options there are for doing that?
Perusing the Field Guide to QBUS and UNIBUS Modules suggests some vintage possibilities. M1801 is listed as a 16 bit reed relay output board. M7843 (DR11-K) looks like a general purpose digital I/O board. It looks like there was a whole bunch of stuff as part of the LPS11 Lab Peripheral System.
I wonder if there were other interesting options. And what are the chances of my finding any of this stuff today? A single eBay search suggests it's all made of unobtainium.
I gambled on an M7985 board off eBay recently for $50 shipped. I think it's a GPIB interface, so assuming that it is, and it works or I can fix it, and I can find/write software to drive it (a lot of ifs!), that will open up options for interfacing with test equipment.
Then there's always the option of talking to things over a serial port. I think that my PDP-11/44 parts heap includes lots of serial ports. But talking to something like an Arduino and telling it to flip relays just sounds like cheating to me.
There's also the nuclear option: What if I made my own UNIBUS card? Don't hold your breath waiting for me to get that done, anybody...
Perusing the Field Guide to QBUS and UNIBUS Modules suggests some vintage possibilities. M1801 is listed as a 16 bit reed relay output board. M7843 (DR11-K) looks like a general purpose digital I/O board. It looks like there was a whole bunch of stuff as part of the LPS11 Lab Peripheral System.
I wonder if there were other interesting options. And what are the chances of my finding any of this stuff today? A single eBay search suggests it's all made of unobtainium.
I gambled on an M7985 board off eBay recently for $50 shipped. I think it's a GPIB interface, so assuming that it is, and it works or I can fix it, and I can find/write software to drive it (a lot of ifs!), that will open up options for interfacing with test equipment.
Then there's always the option of talking to things over a serial port. I think that my PDP-11/44 parts heap includes lots of serial ports. But talking to something like an Arduino and telling it to flip relays just sounds like cheating to me.
There's also the nuclear option: What if I made my own UNIBUS card? Don't hold your breath waiting for me to get that done, anybody...