Search found 6 matches

by lb3361
22 Feb 2021, 01:00
Forum: Kit assembly gallery
Topic: New Gigatron with 128K expansion. Boots from SD!
Replies: 11
Views: 342

Re: New Gigatron with 128K expansion. Boots from SD!

Just to be clear: Marcel designs always gives you bank 0 in the low memory 0x0000-0x7ffff. The video buffer leaves there. The bank bits B[1..0] select what you see in the high memory 0x8000-0xffff. If B[1..0]=0, then you have a copy of the low memory in high memory, like a 32KB Gigatron. If B[1..0]=...
by lb3361
21 Feb 2021, 22:25
Forum: Hardware and software hacking
Topic: New vCPU instructions 2.0
Replies: 10
Views: 510

Re: New vCPU instructions 2.0

The 16 bits stack is a biggie. Will you make it available in the dev rom soon?
by lb3361
21 Feb 2021, 22:10
Forum: Kit assembly gallery
Topic: New Gigatron with 128K expansion. Boots from SD!
Replies: 11
Views: 342

Re: New Gigatron with 128K expansion. Boots from SD!

If you want to retain 100% software compatibility you are left with only 2 choices as far as I can tell. 1) Hide the SDCard routines in bank switched RAM and page them in or out as needed. To me this looks like the most reasonable option because, as you explain, all bytes in the first 32KB are acco...
by lb3361
18 Feb 2021, 17:01
Forum: Kit assembly gallery
Topic: New Gigatron with 128K expansion. Boots from SD!
Replies: 11
Views: 342

Re: New Gigatron with 128K expansion. Boots from SD!

The compact ZIF DIP40 socket is <https://www.digikey.com/en/products/det ... 6-10/20463>.

BTW, the forum software does not let me reply to private messages yet...
by lb3361
18 Feb 2021, 05:18
Forum: Kit assembly gallery
Topic: New Gigatron with 128K expansion. Boots from SD!
Replies: 11
Views: 342

Re: New Gigatron with 128K expansion. Boots from SD!

Well, I thought about the software and I realized that the main problem is the occupancy of page zero locations. Both the native and virtual instruction sets are super dependent on page zero variables. Thanks to CALLI, we could write service routines and hide them in page 3. But they will still need...
by lb3361
17 Feb 2021, 23:33
Forum: Kit assembly gallery
Topic: New Gigatron with 128K expansion. Boots from SD!
Replies: 11
Views: 342

New Gigatron with 128K expansion. Boots from SD!

When I found out about the Gigatron, I knew I had to build one. I ordered a Budgetronics kit and received it a couple weeks later. In the meantime I read a lot from the forums, found out the sad story of Marcel's passing, as well as his latest work. This is when I decided to build a 128K extension t...