joystick problems?

[samplefiend]

Hiya everyone,

Forgive yet anothger query but I got my hands on some joysticks from ebay recently and have been trying them out with some games. The joysticks seem to work fine - control is nice and the fire buttons work great. One thing i've noticed though is that playing with joysticks instead of keys seems to create a lot of background noise in some games.

Devil Assault works without any noise for example. Danger Ranger & Katerpillar Attack make no noise when the stick is to the left but if you move it to the right the noise gets louder. Donkey King and Time Bandit make noise most of the time regardless ...

I've also got a dragon quickshot stick and the same thing happens with it too.

any ideas folks?

cheers again

craig xxx

[munkeyboy]

Hello Craig,

The Dragon uses PIA0 to control joystick and also audio source selection (as well as other things). There is a reference to this in Dragon User August '84 page 45 under the title "Busily buzzing".
I can only guess that some software makes use of the PIA in a different way to others?
My electronic knowledge is limited to say the least, I can't see how it could but does anyone know if this can be resolved with a hardware fix?

Regards, Gareth

[jmk]

That sounds vaguely familiar... When I was programming Glove I found that exact same problem with clicks getting louder as I moved the joystick down or right. It didn't happen under emulation (then, not sure about now) just on the real thing.

I think it's something to do with the joystick taking longer to read when pushing down or right because of the way analogue joysticks work.

I made sure I switched off the 6-bit output (bit 3 of $FF23 reset and I cleared the output ($FF20) just in case) whenever I wasn't outputting any sound and that seemed to fix it, so it's probably a software issue with particular games.

[zephyr]

This problem occurs when games use the BASIC ROM joystick routine. Unlike the CoCo's, the Dragon's joystick routine does not disable audio.

[zephyr]

You can get round this problem quite easily if you have a Dragon 64, or Dragon 32 with a 64K memory upgrade. I have written a small program which copies the BASIC ROM to RAM, and applies a patch to the joystick routine so that it disables audio in the exact same way as the CoCo. This program will stop the clicking sound occurring on most games. Just load, and EXEC the attached 'JOYFIX' before loading your game from disk or cassette.

Regards,
Steve

EDIT: Attachment removed.

[zephyr]

This improved version has the following changes:

(1) Main patch code moved to unused bytes at $9FF8.
(2) Hardware initialisation routine patched to help prevent games from switching the computer back to 32K mode.
(3) RAM test routine patched to prevent ROM in RAM being overwritten if a game were to cold restart the computer.

[zephyr]

Devil Assault works without any noise for example. Danger Ranger & Katerpillar Attack make no noise when the stick is to the left but if you move it to the right the noise gets louder. Donkey King and Time Bandit make noise most of the time regardless ...

I fixed all of these games, except for Time Bandit (The bug wasn't present in my copy), and uploaded them to the Uploads section of the forum.

Regards,
Steve

[samplefiend]

hi again steve,

many thanks for the file and for fixing the fixed dragon games i'd mentioned. it's great to play with the volume loud and not get distracted by the joystick interference!

keep up the great work,

craig xxx