Search found 205 matches

by lb3361
21 Sep 2022, 22:08
Forum: Hardware and software hacking
Topic: Novatron
Replies: 32
Views: 1477

Re: Novatron

I looked again at the novatron schematics (from this thread) and I see that bus0/bus1 are connected to outputs of the U31 gal. I assume that these outputs are only driven when sclk=1 and /oe=0 with. At the same time /woe should be 1 to prevent the ram from driving the bus. Does this mean that bus2 a...
by lb3361
19 Sep 2022, 11:31
Forum: Hardware and software hacking
Topic: Novatron
Replies: 32
Views: 1477

Re: Novatron

The top white row is a page of 0xff that used as input for the spi exchange operation (send 0xff to the card, receive data from the card) The next two rows are the sector buffer. The fact that the gigatron reads constant bytes is highly suspicious since most windows formatters put things there (boot...
by lb3361
14 Sep 2022, 17:09
Forum: Hardware and software hacking
Topic: Novatron
Replies: 32
Views: 1477

Re: Novatron

The sd.vhd image has a proper MBR with a single type 0c partition. Once copied to the sd card, is it recognized by macos or windows? If yes this means that the sd card imaging worked. When booting the gigatron, this image should display "MBR 0C OK". But you get "MBR 0D FAILED". I...
by lb3361
09 Sep 2022, 16:29
Forum: Hardware and software hacking
Topic: Novatron
Replies: 32
Views: 1477

Re: Novatron

Something is wrong. It should be recognizable by both Mac and Windows machines. Did you dd onto /dev/sda or /dev/sda1. Here is exactly what I am doing (my sd card slot appears as /dev/sda). I am also attaching the file sd.vhd.bz2 from https://github.com/lb3361/gigatron-rom/tree/exp/Contrib/at67 beca...
by lb3361
08 Sep 2022, 20:02
Forum: Hardware and software hacking
Topic: Novatron
Replies: 32
Views: 1477

Re: Novatron

This one is different from the one you were testing above because It has no partition table and only contains a FAT32 filesystem. I suggest debugging the novatron with this proven one: https://github.com/lb3361/gigatron-rom/blob/exp/Contrib/at67/sd.vhd.bz2 It should be 64M large after executing bunz...
by lb3361
08 Sep 2022, 08:05
Forum: Hardware and software hacking
Topic: Novatron
Replies: 32
Views: 1477

Re: Novatron

The hex number that is displayed after "Vol.ID" is the logical sector size, as found at offset 0xB in the first sector of the FAT partition. On the Gigatron, this number should be 0x200 (512 bytes/sector). In addition the only legal values there are powers of two. Therefore, if it really w...
by lb3361
22 Aug 2022, 19:14
Forum: Escape Meta Alt Control Shift
Topic: Roadmap and status of Gigatron TTL
Replies: 20
Views: 2697

Re: Roadmap and status of Gigatron TTL

In order to get more space in the ROM, Marcel certainly had the idea in ROM 6 with: Pucrunch (well documented) or eximozer 3.0.2 (better compression) All these decompressors read the bitstream bit-by-bit and therefore need to perform a lot of shifts which can be challenging on the Gigatron. They al...
by lb3361
20 Aug 2022, 04:57
Forum: Hardware and software hacking
Topic: Gigatron Soundcard
Replies: 2
Views: 243

Re: Gigatron Soundcard

Great work :-).
by lb3361
16 Aug 2022, 15:12
Forum: Hardware and software hacking
Topic: Novatron
Replies: 32
Views: 1477

Re: Novatron

The code that tests whether there is a sd card is found in Reset.gcl. It does the things that tiens the card into spi mode, tries the reset command, and checks whether the card answers...
by lb3361
16 Aug 2022, 05:47
Forum: Hardware and software hacking
Topic: Novatron
Replies: 32
Views: 1477

Re: Novatron

1) As long as your only using one spi device, Marcel’s approach works. The miso mux is only needed if you want to put two (or more) spi devices. 2) To use the spi browser, you need the devrom. Then you need to check that the gigatron boot enters CardBoot instead of the main menu when a SD card is in...