Search found 490 matches

by marcelk
13 Apr 2020, 13:03
Forum: Hardware and software hacking
Topic: at67 emulator
Replies: 60
Views: 35273

Re: at67 emulator

The wrapper around Microchess draws the text on the video display. Although Microchess itself is 6502 code, the screen drawing is done by a vCPU function _PrintChar. It shouldn't be too hard to extend this code with a call to SYS_SendSerial1_v3_80 and send that byte out. On the Arduino, you make sur...
by marcelk
11 Apr 2020, 13:32
Forum: Hardware and software hacking
Topic: vasm.py: a mini-assembler for vCPU code
Replies: 4
Views: 4224

Re: vasm.py: a mini-assembler for vCPU code

Although the Python macros are important to me, one reason vasm.py is there is to help another maker boot strap his software stack. I found that asm.py has grown too large to explain the concept. The small 2017 version was really single-person and single-purpose (to build ROMv1). I'm glad we normali...
by marcelk
11 Apr 2020, 13:17
Forum: Kit assembly gallery
Topic: Encore un gigatron, this one from Cologne
Replies: 7
Views: 4424

Re: Encore un gigatron, this one from Cologne

Welcome back! And your assembler is also covered by the FAQ. Documentation wise the project seems near completion.
by marcelk
10 Apr 2020, 20:54
Forum: Hardware and software hacking
Topic: vasm.py: a mini-assembler for vCPU code
Replies: 4
Views: 4224

Re: vasm.py: a mini-assembler for vCPU code

From a different thread: Now we have a assembler to make software using the vCPU instructions, let the fun begin. Of course since 2018 we already have a vCPU assembler, written in C++, as part of at67's simulator suite. Tetronis and Bricks were made with it. I just needed something light and stand-a...
by marcelk
10 Apr 2020, 16:03
Forum: Kit assembly gallery
Topic: Encore un gigatron, this one from Cologne
Replies: 7
Views: 4424

Re: Encore un gigatron, this one from Cologne

They are all covered in the FAQ :D. In short:

A15 is a breakout for expanding the RAM. There is a thread on that here: Double your RAM

You can use CLK2 and ALU7 to make eye diagrams when overclocking:

Eye-74HCT-version.png
Eye-74HCT-version.png (59.55 KiB) Viewed 4396 times

Hope that helps!
by marcelk
08 Apr 2020, 13:38
Forum: Hardware and software hacking
Topic: vasm.py: a mini-assembler for vCPU code
Replies: 4
Views: 4224

vasm.py: a mini-assembler for vCPU code

I always wanted a stand-alone vCPU assembler that can produce .gt1 files. But I didn't want to put effort in writing a front end. So I took the principles from Core/asm.py and created Core/vasm.py . This is (the back end for) a symbolic vCPU assembler. For reference, with 103 lines it is smaller tha...
by marcelk
05 Apr 2020, 12:17
Forum: Hardware and software hacking
Topic: Is the Famiclone controller 3.3V or 5V?
Replies: 2
Views: 2667

Re: Is the Famiclone controller 3.3V or 5V?

Electrically they're all wired the same. But there are at least 3 IC/signal types we're aware of and unfortunately you can't distinguish them by the enclosure. Our early batches had CD4021-type of behaviour. But that can't be the full story when you think of the auto-fire buttons. We always test new...
by marcelk
03 Apr 2020, 15:31
Forum: Hardware and software hacking
Topic: Using a USB keyboard
Replies: 7
Views: 4408

Re: Using a USB keyboard

I sourced a PS2 keyboard (a Perixx Periboard-409) from Amazon. It worked perfectly as soon as I connected it. I spent several hours banging life into Walter's PERIBOARD-409. It wouldn't boot most of the time. I must have booted it 200 times while recording the boot times and conditions. That's when...
by marcelk
02 Apr 2020, 05:59
Forum: Kit assembly gallery
Topic: Another Gigatron is alive!
Replies: 3
Views: 2579

Re: Another Gigatron is alive!

Thanks for the image, I collect those... You mentioned that the keyboard wasn't working at first. In the photo it clearly works. Some keyboards have trouble booting (and a few won't boot at all, not even after 1 minute of trying). See also https://forum.gigatron.io/viewtopic.php?p=381#p381 Did you t...
by marcelk
01 Apr 2020, 14:37
Forum: Hardware and software hacking
Topic: Alternative Languages
Replies: 4
Views: 3153

Re: Alternative Languages

Yes, that all makes perfect sense. I'm continuing to learn a lot from the Gigatron - especially about what is and isn't easy! I'd like to see Forth become a viable alternative to C for writing larger programs on the Gigatron - but C on vCPU, will likely prove to work better in practice. IMHO, C on ...