Gigatron Hackers

Fun and hard like the old days!

P.S: I renamed the game to "bricks" in the repo:
https://www.reuters.com/article/us-nest ... SKCN1AY03D
https://www.reuters.com/article/us-nest ... SKBN1FE24R

This looks neat! I also don't believe the game controller data line is open collector. From all we see it is behaving as if there is a CD4021 inside. Granted, we've put a pull-up resistor R19 on the board, but its intended function is to provide a defined input voltage to the 74HC595 when nothing is...

My confusion is that the early demo (probably in older GitHub revision) predates vCPU. It won't load through an RPi over the input port.

Some magic spells... Double the LED sequence speed: 2f:5 Very slow LED sequence speed: 2f:ff Momentarily switch off the LEDs (until the sequencer makes its next step): 14:0 Replay the startup sound for 2 seconds (120 frames): 2c:78 Shift screen 8 pixels to the right: 101:f8 Shift bottom half of scre...

Congratulations \o/ I'm surprised the RPi can't keep up with all those hundreds of megahertzes it has. Perhaps the critical stuff has to run as an interrupt. Or is there process migration happening between cores? Actually, I have no idea how much delay that gives. It is a pity the Gigatron can't rea...

I've ported the Apple-1 built-in monitor program: WozMon.gcl The original is 254 bytes, my version is $254 bytes :lol:. About half of that is for terminal output (character printing). The Apple-1 had dedicated hardware for that... IMG_3712.jpg This is an extension of the earlier Terminal.gcl program...

As another step towards disentanglement I've just retired the old symbol table (theloop.sym), which was created as a side-effect of building the ROM files. Instead, there is now a checked-in file, interface.json, that takes over its job. With this it should be easier to compile GCL programs directly...

Until I am get into GCL I tried to compile and transfer your little Terminal App called Main.gcl The issue with compiling Main.gcl (now renamed to Terminal.gcl) should be fixed with this: #26 With this, GCL programs can start at addresses other than $0200 again, and the "Loader patch" is ...

This weekend I reworked the Python code that emits the EPROM image (issue #14 ). Historically, from the first Fibonacci algorithm and the first video loops on the breadboard prototype, we've used Python notation for assembly. This way we didn't have to write an assembler, but more importantly, we go...

I replaced the MCP-475 with a MCP-450 and wired it's VCC pin to the debounced RESET button. We're drifting a bit off-topic in this thread, but there is some debouncing provided by the MCP: it has a ~350 ms delay, tRPU in the data sheet, for releasing the /RESET signal. And there still is this 10 ms...