Gigatron Hackers

- The contents of 1F8 is 7C, A15 signal is good in both the IO board (GAL2) and Gigatron Board (pin 7 of U32) This means that the rom detects that presence of the ctrl() instruction. Note that 7C means that bank 1 is selected. Therefore B1 and B0 should be 1 and 0, but.... - After a cold boot pins ...

Another debugging tool is to turn the expansion board into a simple 64k expansion. For this you just need to remove the two GALs and replace them by jumpers according to the attached diagrams. This disables most of the board and merely wire the SRAM like a 64K expansion. Then the Gigatron should dis...

If the Gigatron shows only 32KB, then the card or its RAM was not recognized for some reason. This is unusual. All my cards worked immediately. The interesting thing is that the Gigatron still seems to run. The fact that it can access the RAM proves that a good part of the board is working. There is...

What would have been the price of Gigatron in the 70s? ICs were not as cheap, especially SRAM. Still a good deal compared to a Cray1...

That's probably correct. Modern computers are really fast, especially when they can work entirely from the memory cache...

Did you use the same compilation option -map=64k,hionly as https://github.com/lb3361/gigatron-lcc/ ... e/Makefile ? That shouldn't impact the ratios but make the code a bit faster by avoiding long jumps between screen holes..

8 Bits Audio The last version of the board (see https://forum.gigatron.io/viewtopic.php?p=3014#p3014 and https://github.com/lb3361/gigatron-lb/tree/main/extension-crazy) has a SD Card socket instead of space for a SD Card breakout. This creates more than enough space to for an analog audio filter a...

In files https://github.com/lb3361/gigatron-lcc/blob/master/stuff/sieve/sieve0.c. sieve1.c and sieve2.c, where is the mincprintf() function? The Makefile compiles with option "-Dprintf=mincprintf" which is equivalent to adding "#define printf mincprintf" at the top of the file. ...

You can get a 128KB one and wire the extra address pins together. https://www.digikey.com/en/products/detail/alliance-memory-inc/AS6C1008-55PCN/4234576 Or you can bite the bullet and build a 128KB expansion which also gives you SPI port usable with a SD card. (see https://forum.gigatron.io/viewtopic...

Because I want GLCC to follow ANSI C89, I have to deal with all the formatting complications of function printf. All these rarely used features cost over 2KB in code size. And stdio adds another 2KB code. I already had a function cprintf() which bypasses stdio but still implements all the standard f...