SmartParallel: hacking a Centronics connector

Okay, I lied.

Having ordered the PCBs for my Centronics breakout board, and also having ordered a couple of DB25 breakout boards via Ebay, I settled in for the long wait I knew would follow.

I said in an earlier post that I was getting used to these two to three-week delivery times for stuff coming from China. The truth is, though, that I’ve never been good at delayed gratification.

Most of the…

SmartParallel: Centronics breakout board

Creating a full breadboard version of the SmartParallel board is turning out not to be a five-minute affair. It has to be done meticulously and methodically if it is to have any value as a prototype.

Fitting it all on to a single breadboard is proving challenging too. And that got me thinking.

What about replicating at least part of it on a PCB?

One of the more difficult parts of the breadboard…

DottyMatrix: A simple acknowledgement

Although it was gratifying (and surprising) that my DottyMatrix serial-to-parallel interface worked as soon as I plugged it into an actual printer, there was one nagging flaw. And that was a lack of acknowledgement.

The /ACK signal in the Centronics interface was often sadly neglected, if not ignored completely. But in theory, the sequence for printing a character goes like this (assuming no…

DottyMatrix: It’s alive!

My old, beloved Epson MX-80 F/T III dot matrix printer is back in the land of the living. For now.

As you can see from some of my earlier posts, I’m designing a serial-to-parallel interface with Centronics compatible DB25 connector so that I can print to my Epson from anything with a TTL serial port, such as a Raspberry Pi.

Alas, the Epson belched out a large quantity of smoke, accompanied by a…

Getting to grips with the parallel interface

The Centronics interface seemed such an intrinsic part of a computer’s architecture that, to those of us whose computing coming-of-age was in the 1970s or 1980s, it seemed unimaginable that it would all but disappear. Who knew that serial interfaces would one day reign supreme?

There’s something still very satisfying about hooking up a parallel connection, with fat cables and even fatter plugs…