20 Oct
2007
20 Oct
'07
7:35 p.m.
On 10/20/07, Jim Leonard <trixter at oldskool.org> wrote:
All of these can be hooked up with a serial port, so
I'm still wondering
why today's machines are considered lacking for not having a "user port".
All? Well some of the stuff I hook up to machines lately needs
multiple wires, so unless I want to hack a microcontroller to
interpret serial packets into wire-wiggling (and the attendant drop in
response time to serialize the data to begin with), I'm faced with
stuff that won't fit. The LED scoreboard is a good example of that...
it technically has a bus-type interface (D0-D3, A0-A2, R/W, SEL1,
SEL2...). Essentially, one just needs to pick a chip select, a
register address, then read/write a nybble to make it all work. There
are no serial (or USB) interfaces for it.
OTOH, an 11-wire cable to a PC parallel port (being used as a 'user
port', not a printer port), and some very simple software to read and
write the port registers, and it's a fully functioning peripheral.
Can I make a microcontroller to talk to it via serial? Yes. Is it
more work than an 11-wire parallel cable? Absolutely.
-ethan