I bought a copy of this book last year from AbeBooks:

http://www.abebooks.co.uk/

But it seems that they don't have another one for sale at the moment.

Was it just a page or two that you're interesed in? Or do you need the whole book?

Looks like a nice chip! But what package is it in? The data sheet doesn't seem to say. Or should we start looking for TV games in the shops, that contain this chip so that we can open up the game and get hold of the chip that way?

Here's a web page with lots of information about the 8-bit sound chips:

http://www.srcf.ucam.org/~rga24/computer/music/

But, the data sheets all give me a 403 (permission denied) error. Hopefully that'll get fixed soon.

Well done for rescuing and fixing up that SYM-1! I have one here, too, that was used in education -- but wasn't used for soldering practice.

As for the AY-3-8912, there's an AY sound chip home page here:

http://bulba.at.kz/main_e.htm

maybe there's a circuit on that site?

John Honniball

I like the suggestion to connect up an AY-3-8910 Programmable Sound Generator. But there are other choices: how about connecting a SID chip from a junked Commodore 64? Or you could use the TI sound chip, the SN76477:

http://www.mkv.mh.se/staff/per/diy/76477/

A similar chip, the SN76489, was used ...

Also, does anyone know of a compact, easy to use, 6502 compatible keyboard and the best way to supply five volts of power from a battery, thanks.

If you add an 8-bit output port, and an 8-bit input port, you can design a software-polled keyboard. That'll allow you to use any matrix layout you ...

Yes, I still have a SYM-1! And a KIM-1, and a UK101. But the Acorn System 1 has been upgraded (by the original owner) to an Acorn System 3.

The Commodore 64 did something like this, they took 9VAC from the power supply and ran it through a schmitt trigger to create 60Hz clock pulses for the 6526 TOD counter.

Which is fine until you run your code on a Commodore 64 in Europe and the interrupts come in at 50Hz. Did the C64 ROM correct ...

Surely $FF is an invalid BCD number to begin with? Which means that adding one to it is undefined, and can vary from one 6502 (or 6502-like) chip to another.

What happens if you load the accumulator with, say, $42 and add one?

I havn't used 'nesasm.exe' myself, but it looks like it's a console application, not a GUI application. This means you'll have to run it from a command prompt window. Open a command prompt, then use 'cd' to navigate to the directory where 'nesasm.exe' is located, then type 'nesasm' and see what ...

The power supply switch-on transient can affect crystal oscillator start-up. I've seen a crystal oscillator circuit that would start up just fine on one type of PSU, but refuse to work at all on another. There was a modified circuit that had to be used in that case.

Have you tried the 6551 on a ...

Just a minor detail, but the board you've shown is from an Apple ///, the succesor to the Apple ][. Both were based on the 6502 chip. The Apple Lisa was a much more powerful machine based on the 68000 chip, and with a bit-mapped display and a mouse.

Shame to hear that your friend scrapped the ...

You didn't say in your original post that the 6522 must be programmed to generate the IRQ. I'd assumed that external logic did that.

But, as far as I know, the 6522 can't generate interrupts when the bits of a port change state. I know that the BBC Micro, for instance, has a NAND gate that ...

For a really simple bus, how about the S50 bus that was used in many SWTPC 6800 and 6809 computers in the early 1980s? Just wish I could find a reference to it on the web! There's an SWTPC web site here:

http://www.swtpc.com/mholley/index.html

Ah! got it:

http://retro.co.za/6809/documents/ct ...

Well, if it's an Apple ][ style keyboard that you need, why not get an old Apple ][ and use the keyboard? Apple][s are quite common, so I understand, and you wouldn't even need a complete or fully-working one.