Search found 474 matches

by marcelk
Today, 12:17
Forum: Hardware and software hacking
Topic: Is the Famiclone controller 3.3V or 5V?
Replies: 1
Views: 48

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: 5
Views: 91

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: 64

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: 118

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 ...
by marcelk
01 Apr 2020, 12:10
Forum: Hardware and software hacking
Topic: Alternative Languages
Replies: 4
Views: 118

Re: Alternative Languages

For vCPU we purposely went for a model that encourages to put everything important on fixed locations in zero page. For small programs on small computers, that is perfectly fine. And that's why the GCL notation doesn't even bother with scoping. Still you can do recursion if you want, using LDWL, STW...
by marcelk
27 Mar 2020, 06:06
Forum: Hardware and software hacking
Topic: Python Assembler Query - RAM labels
Replies: 10
Views: 233

Re: Python Assembler Query - RAM labels

Perhaps ASM.py can be modded to warn on page faults for branches. That's a good point. There's a small dilemma here between chopping off the high byte when resolving symbols, vs. requiring the high byte to be zero or match the page number. We chop off the high byte now because that has many uses. d...
by marcelk
26 Mar 2020, 09:49
Forum: Hardware and software hacking
Topic: Python Assembler Query - RAM labels
Replies: 10
Views: 233

Re: Python Assembler Query - RAM labels

This is a long time ago.... Internally the ROM bytes are kept in two lists, _rom0 and _rom1 for the even and odd bytes. _romSize = 0 _rom0, _rom1 = [], [] This goes back to the breadboard with two 28C64 chips: ROM0_ROM1.jpeg The way it is now, _rom0 and _rom1 start out empty and the assembler append...
by marcelk
24 Mar 2020, 16:03
Forum: Hardware and software hacking
Topic: v6502 mini-assembler in Apple-1 emulator
Replies: 3
Views: 1296

Re: v6502 mini-assembler in Apple-1 emulator

The mini-assembler's usage is now displayed when starting it with EEER. But you can skip this with an easy-to-remember alternative entry point. When toying with 6502 code and making mistakes, the system appears more stable than I expected. This is because in v6502 practically all invalid instruction...
by marcelk
24 Mar 2020, 09:01
Forum: Hardware and software hacking
Topic: Interrupts:
Replies: 8
Views: 1981

Re: Interrupts:

marcelk wrote:
18 Feb 2020, 11:34
After experiencing the impact on Apple-1 Integer BASIC, I'm strongly thinking to move the $00FC-$00FF vIRQ locations to $0030-$0033. Any objections, please shoot...
Relocation is now done including documentation and example code. This also fixed `AUTO'.
by marcelk
22 Mar 2020, 07:59
Forum: Escape Meta Alt Control Shift
Topic: Two years of kit making and Open Source Hardware
Replies: 5
Views: 249

Re: Two years of kit making and Open Source Hardware

Although we don't "target" schools at all, quite a few buyers are teachers and school departments! We have plenty of ideas, big and small. But an idea is of very little value unless you commit to it yourself. For example, I'ld love to build a discrete transistor Gigatron at full speed. But something...