exxos's Atari, Amiga & retro forum

stephen_usher wrote: 07 Mar 2022 23:11 Being able to capture 16 channels at a time helped, as was the ability to export to CSV. Once I had the 1s & 0s in a parseable format Perl was the obvious choice.

For each entry where the serial chip 1 write line was active (active low) I either added 1 to a variable holding the value for another line if it was high or subtracted 1 if low. Then after doing this for every entry divided the counts by the number of entries. Any value which wasn't 1 or -1 I knew didn't fully correlate with the signal I was interested in. It also gave the sense (high or low) relative to the target signal.

Sounds really neat, I definitely need to improve my LA skills, though I suspect Python would be my choice for manipulation as I already do some at work :)

Perl is ideal for this as this is the sort of thing it was designed for.

For years I've had an Eiffel interface for the TT but never used it, even though I fitted it into a case, as it seemed to crash all the time when using it with a Compaq PS/2 keyboard and a Genius mouse.

Last year, whilst tinkering with a PC I found that the Compaq keyboard wasn't reliable and kept crashing (and taking the PC with it) so deemed that to be faulty.

Anyway, recently the TT keyboard + mouse has had an issue where it has a phantom right-mouse-button press almost continuously. Sometimes a power cycle of the TT would fix it, sometimes not. Unplugging the keyboard and plugging it in didn't reset the problem. The issue has been getting worse over time.

So over the last week I've tried going back to the Eiffel, but this time with an Acorn RISC PC keyboard (I don't have the RISC PC unfortunately). With this keyboard the Eiffel is working flawlessly... and no phantom right-button held down, which really shows that something must be amiss in the TT keyboard.

I wonder what the TT keyboard problem could be. Something on the power rail? Bad pull-up resistor on the mouse port?

I know that if I have a Tom+ adapter plugged into the mouse port the keyboard doesn't work when I turn on the computer, I have to plug the Tom+ in afterward. (Yes, the mouse plugged into the Tom+ shows the same phantom right-button press).

Interestingly, the mouse right-button seems to be directly wired to the controller chip, unlike everything else which go through a 74LS244.

The C64 SCART cable has arrived, at last.

stephen_usher wrote: 10 Mar 2022 09:46 Interestingly, the mouse right-button seems to be directly wired to the controller chip, unlike everything else which go through a 74LS244.

How odd. Cost cutting exercise by Atari perhaps?

I guess that they didn't want to add another 244 when there was only one line, so they thought that they'd wing it I imagine.

I'll have to open the keyboard up and see what the voltage levels are like I may have to swap the 10K pull-up with a 4.7K one.

Icky wrote: 10 Mar 2022 18:20

stephen_usher wrote: 10 Mar 2022 09:46 Interestingly, the mouse right-button seems to be directly wired to the controller chip, unlike everything else which go through a 74LS244.

How odd. Cost cutting exercise by Atari perhaps?

(Assuming you are talking about the ST keyboard)

No, not really. The '244 is there just for the purpose of multiplexing, not for buffering. There is not enough I/O ports in the IKBD controller for all the signals. So the IKBD chip controls the '244 Output Enable. It disables the '244 when it wants to read the keyboard matrix, and it enables it when it wants to read the mouse and joystick signals. There is no need to multiplex more than 8 signals, so the rest can go directly.

I see.

Still, I'll have to check the voltages.

In other news:

It looks like on Saturday I'm off back to where I used to live to pick up a whole load of stuff from a school colleague's parents' house. I either rescue it or it gets skipped.

Mac LCII + colour monitor and ImageWriter printer. (Goodness knows how battery damaged the LCII will be!)
BBC Micro with floppy drives and joysticks.
TI 99/4A with stuff.
TM 990/189 board computer with power supply (never heard of this)
TI 59 programmable calculator
Epson LX80
Loads of manuals.

Most of it in the original boxes!