Search found 197 matches

by lb3361
16 Aug 2022, 15:12
Forum: Hardware and software hacking
Topic: Novatron
Replies: 12
Views: 205

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: 12
Views: 205

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...
by lb3361
15 Aug 2022, 08:15
Forum: Hardware and software hacking
Topic: Novatron
Replies: 12
Views: 205

Re: Novatron

There is also a bit of a problem about the MISO lines. Marcel used to pull them down and route them to bits 0 to 3 of the bits when sclk is high. The rom code assumes that the only non zero MISO must the one from the active spi device, and therefore can be tested with a simple anda(0xf). Alas many d...
by lb3361
14 Aug 2022, 06:10
Forum: Hardware and software hacking
Topic: Novatron
Replies: 12
Views: 205

Re: Novatron

Oh I see. No level shifters because the 74f series (and other ttl) have a lower Voh than the 74hct ones (and other cmos).
by lb3361
13 Aug 2022, 13:56
Forum: Hardware and software hacking
Topic: Novatron
Replies: 12
Views: 205

Re: Novatron

Very nice.

I wouldn't burn the SPI SD card browser in the Rom. As long as Cardboot is there, it is enough to put it on the SD card itself. Si the DEVROM should do...

Did you use level shifters for the sd card signals MOSI, SCLK, /SS0 ? I believe one has to...
by lb3361
28 Jul 2022, 13:00
Forum: Escape Meta Alt Control Shift
Topic: Roadmap and status of Gigatron TTL
Replies: 18
Views: 1873

Re: Roadmap and status of Gigatron TTL

The current DEVROM is not far from a ROMv5. See the updated TODO list at https://github.com/kervinck/gigatron-rom/blob/80b46b561ebcbd5cfc7f8e2150d81b328815fc42/Core/dev.asm.py#L91 . Compare with the ROMv5a status https://github.com/kervinck/gigatron-rom/blob/80b46b561ebcbd5cfc7f8e2150d81b328815fc42/...
by lb3361
14 Jul 2022, 00:36
Forum: Hardware and software hacking
Topic: Debugging symbol format
Replies: 5
Views: 136

Re: Debugging symbol format

In GCL you have two things, variables and symbols. Variables are in a dict named 'program.vars' that could be printed with an additional option in 'compilegcl.py'. Symbols seem to be mingled with the native symbols and accessible in a dict named '_symbols' imported from module 'asm.py'. This module ...
by lb3361
13 Jul 2022, 21:09
Forum: Hardware and software hacking
Topic: Debugging symbol format
Replies: 5
Views: 136

Re: Debugging symbol format

GLCC option --syms prints a symbol map. Option --frags tells you where all modules go in memory. The compiler is based on LCC which has ways to output more detailed debugging information into the .o files (stabs format). This is currently not used because one would also have to write a source code d...
by lb3361
28 Jun 2022, 20:56
Forum: Hardware and software hacking
Topic: Gigatron Clone Ideas
Replies: 46
Views: 2213

Re: Gigatron Clone Ideas

The v3/v4 Picture application makes heavy use of the SYS function SYS_Read3 and SYS_Draw4 to display four consecutive pixels. The v5a version does not. In particular SYS_Read3 uses a complicated system of trampolines that might test the jmp instruction.