Pinned toot

I think we are feature- and bug-complete for the first part of the UI, which is the pattern editor. I'll get this ready for release and push master.

This makes vtracker a bit more usable, but it still needs an instrument editor and track editor before it has a complete user interface.

Pinned toot

Board layout is planned. Just waiting on a few more WW headers and sockets to arrive before I start building.

The new board is here. Still waiting for WW wire and sockets to begin.

Did some testing with AY-3-8910 this morning. It's nice to have an extra effective channel vs. the SN76489. Disappointing that there's not a separate envelope for each channel, and it takes 3x the board space of the SN7.

I'm unsure whether I'll proceed with the AY or the SN.

I'm up to 7 breadboards and 11 ICs. The scope shows how sloppy the clock signal gets as it goes over long wires from the oscillator to the I/O and sound chips. I've seen no functional problems at 1 MHz system clock, in spite of this.

Show thread

This 65C02 computer circuit has outgrown breadboard construction. There are 5 chips on the top right almost completely hidden by bus cables. I'm not yet ready for PCB. Starting next week, I'll move this to wire wrap on a perfboard. Wire wrap supplies are ordered and on the way.

I made my first prototype music player for my f1 6502 machine. The audio hardware is a single SN7 for now. I'm quitting for now and will continue next Friday.

I have a minimal little tracker running. I realized it would be very easy to add another SN76489 for more polyphony and stereo, so I may try that soon.

Show thread

Using my 6502 computer to make some music on the SN76489 chip today.

A quick search suggests it costs less to get multiple smaller PCBs than a single larger one. If I go with PCB, I may put processor, VIAs, CIAs, ROM, RAM, and addressing decoding and glue logic
on one board, the LCD on another board, forthcoming sound generation hardware on a
3rd board, and so on.

If I go with wire wrap instead, increasing prototype board size doesn't affect cost as much.
So I might try to get everything I can on one board.


Show thread

This morning, I wired 65C51 and 65C22 IRQ lines with AND logic and then tested handling interrupts from both in software. I'm a step closer to having the connections for this machine finalized
and moving from breadboards to either wire wrap or PCB, neither of which I've done before.

Now that I have desktop -> 6502 serial program transfer working, I can test code much more quickly. Time to start working on LCD display routines.

Looks like the display memory is mapped funny, so the auto-increment feature goes from line 1, to 3, to 2, to 4. I'll need to manage the display memory manually.

Still waiting for my SN76489s to arrive, but I also ordered 2 AY-3-8910As and a YM2149, which are also compatible with my planned 1 MHz clock speed. All are from Chinese sellers, so I'll be waiting a few weeks until I can experiment. Anyone used the AY-3-8910A before?

Working with some instruction timings with a small Python script I made for this purpose.

I tested the SN76489ANs I bought last October. Unless I'm doing something very wrong, they seem to be fakes. Disappointing, since I was hoping to add one to my 6502 computer this weekend. I ordered a handful more from a top-rated eBay seller, but it'll be at least a couple weeks until they arrive.

Looking forward just a bit, it seems like my two next best prospects after breadboards are PCB or wire wrap sockets. I'd like to try wire wrap, but the IC sockets are $2-$3 each.

Today's been a productive day for my 6502 machine. I added RAM to the circuit, so now it'll run programs that use the stack. I tested both a faster timer-based clock and a 1 MHz oscillator can; both work. I finished basic UART program transfer routines and tested them in the emulator, so the next thing to do is add the MAX232/65c22 to the circuit and try transferring a program from desktop machine to 6502 machine.

Show thread

Continuing to work on RS-232 support in the emulator for my 6502 machine. The UART communication is implemented using named FIFOs.

Implemented basic 2-way communication between my desktop and a microcontroller using the w65c51/max232. Now that I understand these chips, the next thing is to add support for them to the emulator for my 6502 machine. Then I'll write and test the serial port routines before moving it all over to hardware again.

Show thread
Show more

Fosstodon is an English speaking Mastodon instance that is open to anyone who is interested in technology; particularly free & open source software.