After nearly 2 years away, I finally got the Rockwell 6551 working

We moved around 2 years ago, and all my stuff got packed up and put on the bottom of a stack of bins. I finally dug it out this week to make another attempt at getting the Rockwell 6551 working with interrupts instead of transmit polling. I eventually want to interface with my DECwriter that only goes up to (I think) 300 baud. That's a lot of polling. I also have plans to make a baud rate detection routine. "Press X to set baud rate" repeated at different speeds until it gets "X" back.

Anyway, I had Claude look at all my code since the beginning and give me a test routine to see if the Rockwell chip would work. I don't have the clearest memories of 2 years ago, but the first thing I noticed when getting it loaded and running was that IRQB on the 6551 wasn't even wired up to anything. Gee, that could have had something to do with it. I also had some floating control signal pins, and got those tied down correctly.

The test code ran beautifully the first time. I promptly deleted it (in fact, I'm not even 100% sure it was using interrupts). I want to be able to understand everything that's happening in my code, so now I'll be going back through most/all of Ben's videos and doing it all again to refresh my memory.