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Zolatron 64 #6502 #homebrew - serial port part 2 - writing assembler code

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 send a fixed message out over the serial port. The code is up on GitHub – it’s the z64-02.asm…

Zolatron 64 #6502 #homebrew - better LCD printing #8bit #computing

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 move on to doing something a little more interesting. But first, I had a problem to solve. Something’s…

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 the fickleness of their logic until, at last, I saw…