Hello all, I've been playing around with some ideas for designing some hardware to connect peripherals to an fpga for my vhdl pdp-11. One of the things that should definitely be on there, next to sd cards and leds... are some serial ports for console terminals etc. I've spent some time to create a prototype usb to serial thing that handles more than one port. Works kind of neat.
While doing that, I stumbled on the concept of break. Up to now in all of the pdp2011 history I have ignored it, the serial port that sits at the pdp-11 side of things is about the most minimum that does the job. And that is good enough for a lot of things, actually - I didn't really miss a break signal so far. Anyway, digging through the documentation of KL-11 and DL-11 I did find references to generating a break (bit 0 in the XCSR). But not on how it would be received. That's where the questions start. How did a DL-11 like interface signal the reception of a break? And how did the operating systems and software deal with it? Was it actually used at all? I think to remember several occasions of impatiently banging the break key back in the day, but it is a bit fuzzy why (and if it had any result). anyway, I'm trying to judge whether it makes any sense to put effort into making the break thing work on my serial converter thing... any kind of input is greatly appreciated! cheers Sytse