Tag Archives: printer

DottyMatrix: a simple solution?

The DottyMatrix project began when I thought, ‘It would be nice to make use of my old Epson MX-80 F/T III dot matrix printer’. The problem was talking to it. But then I thought, ‘It’s just parallel printer interface. I’ll make a microcontroller-based device to act as an interface. How hard can that be?’. The answer, it turns out, is… Read more »

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… Read more »

DottyMatrix: Printing to an actual printer

It seems the repairs to my venerable Epson MX-80 F/T III dot matrix printer did actually work because it’s now printing again! What’s more, it’s printing via the prototype of my DottyMatrix serial to Centronics parallel interface. Time for a quick recap. The DottyMatrix is based around an AVR ATMEGA328PB microcontroller. It takes input on a TTL-level serial connection and… Read more »

DottyMatrix: It’s alive!

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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…. Read more »

DottyMatrix: ghost of the typewriter and the curse of the carriage return

In designing my DottyMatrix serial-to-parallel printer interface, I had to decide how it would handle the incoming data stream. The purpose of the DottyMatrix is to connect my venerable Epson MX-80 F/T III dot matrix printer to (probably) a Raspberry Pi so that I can print out text files, such as program listings. Obviously, it would be good if it… Read more »

DottyMatrix and Virtual Printer – together at last

It’s great when a plan comes together. Having independently played around with my DottyMatrix serial-to-parallel printer interface and the Virtual Printer (designed to simulate my still-dead Epson MX-80 F/T III dot matrix printer), it was time to hook them together. And it worked! On the left is the DottyMatrix using my prototyping board for the ATMEGA328PB microcontroller. Its serial port… Read more »

Virtual printer & more fun with AVR interrupts

In building my AVR ATMEGA328P-based ‘virtual parallel printer‘, there were two signals that required special treatment. So it was time to revisit interrupts. On a Centronics-style parallel port, the host machine sends an ‘init’ or reset signal to the printer to tell it to flush its buffers and set itself to the default state. It also sends a ‘strobe’ signal… Read more »

Building a virtual parallel printer

Here’s a tip for anyone building a device designed to interface with a parallel printer – you kind of need a parallel printer to test it on. That shouldn’t have been a problem. My DottyMatrix project – which will allow me to send data over a serial connection and have it printed on my Epson MX-80 F/T III dot matrix… Read more »

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… Read more »

Epson MX-80 Part 4 – ESR check of the dodgy caps

It seems strange that both the capacitors and the transformer – the chief suspects in the investigation as to why my Epson MX-80 F/T III dot matrix printer belched out smoke – tested fine with a multimeter. As far as the capacitors were concerned, I measured resistance directly across their leads (having removed them from the circuit board) looking for… Read more »

Epson MX-80 Part 3 – well, this is strange

And so to the next instalment of trying to get my Epson MX-80 F/T III dot matrix printer back up and working. Previously on Epson MX-80… Just over a year ago, lots of smoke came out accompanied by a crackling noise. I’ve removed the main smoothing capacitors from the PCB and tested them. They seem fine. I tested the transformer…. Read more »

Epson MX-80 Part 2 – out damn cap

Time for the next step in my attempt to bring my beloved old EpsonMX-80F/T III dot matrix printer back to life. But first, some pictures of gorgeous old retro components. As we’ll see, they might be all I have left. I do love old resistors. They have so much character. And look how thick the wires are. There’s also a… Read more »

Epson MX-80 Part 1 – resurrecting an old friend

It’s hard to lose an old friend with whom you’ve shared more than a  third of a century’s worth of experiences. I’ll never forget the day it happened. I heard a coughing, spluttering noise, turned around and, sure enough, smoke was pouring out of the printer. And not just any old printer – my trusty Epson MX-80F/T III, the first… Read more »

Serial to parallel the hard way

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I kind of miss making hard copies of my program listings on a dot matrix printer. There’s something contemplative and satisfying about waiting for the printer to finish its buzzing and chattering so that you can pore over the code and find that bug. Also, printouts on continuous listing paper with holes down the sides feel like real computing. It… Read more »

Goodbye old friend – the death of a dot matrix printer

It’s one of the curses of getting older. One by one your friends die around you. This time the bell tolled for my beloved old Epson MX-80F/T III dot matrix printer. It’s hard to express how much this delightful old beast means to me. Buying it was a huge step because it was so incredibly expensive (kids who buy printers… Read more »