Gigatron Hackers

Testing has progressed. We can run Microchess now. Video: https://youtu.be/KBdDg5JfVs8 Screenshot 2019-07-11 at 17.06.35.png Changes are: It runs in full On true TTL :-) Without VGA timing errors Microchess is about 1K in size and was written in 1976 by Peter Jennings for the KIM-1. The 6-digit hex ...

All sounds good. Good luck!

steve wrote: ↑10 Jul 2019, 17:27 a real keyboard for me should a must in a computer while the current joypad seems more console oriented.

I just hope you didn't miss that we added the PS/2 keyboard interface about one year ago.

We can squeeze in at least two new vCPU instructions without breaking compatibility of existing GT1 files. We can do this by diverting INC and ALLOC, after entry, to another page and continue there. This makes them 6 cycles slower in total, but we can reuse the won space as the landing spot for new ...

I was pondering about a future "real" ROM upgrade once the SPI interface and RAM expander hopefully have software support. This is probably not sooner than end of this year, because we need the C compiler to work better for that first. (We can use some help there BTW). Assuming we make it ...

Welcome to the club! The Gigatron design is easy to expand, because so much was stripped away from it :D Some links to interesting earlier proposals: tocksin's: https://forum.gigatron.io/viewtopic.php?f=4&t=56 hgm's: https://forum.gigatron.io/viewtopic.php?f=4&t=6 As far as I know, both have...

vCPU schedules its instructions in the dead time between horizontal sync pulses surrounding pixel-less scanlines. Depending on the scanline type, 100-148 cycles are available for this purpose (out of 200 cycles per scanline). The remaining cycles run instructions to keep the video signal alive, and ...

We do have an inverted clock, but it's also created by an inverter (U1). You can try and characterise a 74x241. One of its enable pins is positive, the other negative. You might be lucky if their propagations are the same, but a quick first glance at the 74LS and 74HCT data sheets is discouraging. S...

Thanks for sharing your build pictures! My guess is that option 3 gives the quickest results with "OK" performance, and it's not harder than 1. There's no need to go through an external file format first (.vasm, .gcl). Although some recent changes to "gcl0x" make it more suitable...

Today's HaD coverage made me realise lots has happened last week. HaD-20190703-small.png Recent developments include: All MOS 6502 instructions, addressing modes and flags are implemented (*) Not all are fully functionally tested yet, but timing-wise (with respect to VGA) it all looks good We do hav...

v6502 now manages to run wozmon. We already have a built-in WozMon of course, but that's a rewrite in GCL/vCPU with extra features (such as backspace). This is the original Apple-1 wozmon running in v6502 land. This means you can use it to toggle in MOS 6502 code and run it with R. Of course I neede...