Zolatron 64 6502 homebrew – parsing inputs in assembly

Okay, so this is going to be a long one. Grab a coffee, settle down and we’ll begin… The last time we talked, I was able to send messages to the Zolatron 64 6502 homebrew computer via its serial port. But all it could do was print those messages to the LCD screen. It’s time to actually do something with… Read more »

Zolatron 64 6502 homebrew – a terminal of my own

Early on in the design of the Zolatron 64 6502-based homebrew computer I made the decision that I wasn’t going to bother with attaching a keyboard and monitor. It has a 16×2 LCD display for small stuff. Otherwise, I/O was always going to be via serial. That means talking to the machine via some kind of terminal software. To date,… Read more »

Zolatron 64 6502 homebrew – even better LCD printing

Many thanks to reader Michael McLaren for giving me a heads-up about a better way to move the cursor on the LCD display. In an earlier post, I described how I was using the ‘shift cursor right’ command multiple times to put the cursor in the desired position – mainly so that I could use the second line of the… Read more »

Zolatron 64 6502 homebrew – converting between text and numbers in assembly

One thing it was obvious I would want to do with the Zolatron 64 6502 homebrew computer is have a routine to display the contents of sections of memory – à la Wozmon. There’s a snag, though. The content of any given byte in memory is a number, in the range 0-255. But to display this on the screen, this… Read more »

Zolatron 64 6502 homebrew – better LCD printing

A quick recap. The Zolatron 64 6502 homebrew machine is at the point where it can print messages to an LCD screen and send and receive messages via the serial port. Most of the time. The incoming messages are put in a buffer and then printed to the LCD. And a fat lot of use that is. I wanted to… Read more »

Zolatron 64 6502 homebrew – serial port part 3

Listening is so much harder than talking, don’t you think? That’s how it turned out with the Zolatron’s serial port, anyhow. Getting the computer to send messages was pretty easy. Receiving them? Not so much. The first stages of developing the software were typical. I wrote code that I knew should work. It didn’t. I cursed the binary gods for… Read more »

Zolatron 64 6502 homebrew – serial port part 2

It didn’t work. Not straight away, anyhow. Once I’d wired up the 6551 ACIA chip, my UART of choice to give the Zolatron 64 a serial port, I threw together some code to test it. It was pretty simple – it took my already known-good code that prints a message to the LCD and added to that a routine to… Read more »

Zolatron 64 6502 homebrew – serial port part 1

So far, the Zolatron 64 6502-based homebrew computer has output (a 16×2 LCD screen) but nothing in the way of input. I have toyed with the idea of getting it to output to, say, HDMI using a Teensy as an intermediary. And also of giving it a PS/2 keyboard input (the latter still being a possibility). But in the end… Read more »

My favourite Raspberry Pi 4 cases

Every Raspberry Pi deserves protection. Having used these boards since the first iteration, I have tried many cases over the years, all of them with their strengths and weaknesses. Now I’ve settled on a couple of firm favourites – both from Argon40. And to get this out of the way up-front, this post is not sponsored in any way. I’m… Read more »

ESP32 room thermometer: with 18650 battery level indicator

It seemed like a good idea at the time. The TTGO ESP32 microcontroller board that I’m using for a room thermometer project comes with a battery connect and charging circuitry for a Li-Ion cell. It would be so much easier to deploy the thermometer if I could run it off a battery. And it works. Kinda. There are issues, though…. Read more »

Network monitoring #2: Logging CPU temps with InfluxDB and Grafana

My previous method of logging the CPU temperatures of machines on the network involved a Bash script sending out a message via MQTT. This was intercepted and logged by a Python script running on a server, which wrote the data to text files in a place where the intranet server could see them. Phew! It’s a miracle it worked. But… Read more »

Battery-powered ESP32 IoT room thermometer with OLED display

A while back, I made a couple of ESP8266-based room thermometers. These have been beavering away happily ever since – one on the desk in my office and one in the living room (or salon as we say in France). The only significant change I’ve made to them is to add the capability for them to report temperatures to an… Read more »

Network monitoring #1: Server temperatures, MQTT and Bash

It’s always a good idea to know the state of the machines on your network. Plus, I’m a geek, and messing around with data appeals to me. One metric I especially like to keep an eye on is CPU temperature. Why? Why not? I’ve recently got into InfluxDB and Grafana, and that’s the way all future projects will be going…. Read more »

Are my lightbulbs phoning home?

      5 Comments on Are my lightbulbs phoning home?

Just lately I’ve been getting into home automation. No, not with ESP8266s and lots of soldering and programming – that comes next. I mean the easy way, by buying smart lightbulbs and switches. We have an old, dark house, which means we use a lot of lamps. Every morning, in the living room alone, we’d go around switching on seven… Read more »

The Dawnclock – back from the dead

I’d been waiting for this moment. I’m not a electronics or coding expert and so, sooner or later, I expect all of my projects to die. But the Dawnclock just kept on living – right up to the point when it didn’t. I first blogged about this project in January 2013, which means that it’s been operating for eight years…. Read more »