falter
Veteran Member
Can anyone sort of explain to me how a typical serial i/o works with a UART like the AY-1013 ? I'm trying to track down the problem with this machine. It seems to receive - although it is getting the incorrect characters (like it gets a weird character instead of the $ prompt for SWTBUG). So I have two working theories - one is that the transmit part of the circuit just isn't working, the other is that there's some kind of memory fault and when I type it's trying to transmit the wrong characters and the computer just is ignoring it.
What I can see when I type are the bits being set up on DB1-DB8, and they stay that way until the next keypress. I am not seeing a strobe. I've got an MC1488 and an MC1489.. I assume the MC1488 is on the transmit side so that'll be the next thing I check out tonight.
What I can see when I type are the bits being set up on DB1-DB8, and they stay that way until the next keypress. I am not seeing a strobe. I've got an MC1488 and an MC1489.. I assume the MC1488 is on the transmit side so that'll be the next thing I check out tonight.