Gigatron Hackers

I have the nagging feeling that the low-pitch noise might be caused by the mismatch between 521 scan lines and 4 sound channels. Every 16.7 ms there will be an interval of 5, not 4, scan lines that are together producing a sample. That can and will overflow. The solution I had in mind is that the vi...

Could you elaborate a little about which problems may I expect if using sockets? Mechanically it needs more care. It is easier to bend or break a pin on insert, or miss that a pin is not inserted at all but dangling on the side. It is much simpler to put an IC directly into the PCB without errors t...

More ideas to win speed for your Hackatron Grand Master (HGM):

1. Hookup a different type of output device so you don't need to worry about VGA signals (LCD or OLED display with I2C or SPI)
2. Faster chips

Contrib/ it is!

Phil's is also live on the web page under "Home": https://gigatron.io/ It works fine with Chrome and Firefox, but there seems to be an issue with Safari. We also have Martin's that is listed under "Tutorials", bottom of the page: https://gigatron.io/?page_id=574 This is the one w...

at67 has extensive developments in his fork of gigatron-rom. There are other people doing similar things as well. Those developments are largely orthogonal to what is already there and I see two ways we can go with this: 1. Keep independent developments separate in independent trees. Reject the pull...

keyL:keyH -- 15-bit frequency (bit7 of keyL should be 0). There is a lookup table on page 7 in ROM oscL:oscH -- 15-bit phase, automatically incremented with keyL:keyH every 4 scan lines (1 channel per scan line) wavX -- Modulation of index with XOR operation wavA -- Modulation after table lookup wit...

I've blown a few that way judging from my damaged parts jar.

We knew we were not going to get anywhere near the MOS 6581 of course, but this is GREAT beeping! Indeed, setting the key to 0 Hz acts as OFF for the channel. With that, the soundTimer control variable is merely a convenience for simpler programs. It is a minor inconvenience if you don't want it to ...

In the Ben Eater series you can see the he doesn't use resistors. That is a bit of a poor practice, but he gets away with it because he has older 74LS chips that don't deliver much current in the first place. And probably his LEDs need a lot and he uses a juicy USB charger. With the chips in the kit...