Incognito - 4th joystick button for disk change?

[Xebec]

Dear Atarians -

 

Is there any technical feasibility or possibility to ask that a joystick attached to port 4 on the Atari 800 w/Incognito could be used as a button for the floppy disk swap (rather than wiring in a button or similar)?   Can that be done via software only?

[flashjazzcat]

If you can make it latch the button register, no reason why not. The software expects the latch to be set and that won't change.

[+Faicuai]

58 minutes ago, Xebec said:

Dear Atarians -

 

Is there any technical feasibility or possibility to ask that a joystick attached to port 4 on the Atari 800 w/Incognito could be used as a button for the floppy disk swap (rather than wiring in a button or similar)?   Can that be done via software only?

In XL/XE mode, that joystick port (e.g. button/trigger) is NOT addressable with Incognito's current implementation.

 

I recall, when inspecting not just this issue, but also full joystick support on all front ports (in XL/XE mode), that I could read joystick button actuations up to Port #3, and had to be read directly from a specific (high) address space.

 

There is a way to instruct the system to change its operating mode (via HW registers) and start reading all joystick ports on XL/XE mode, but it turns out that in Port 3 or Port 4 there is ONE direction (joystick) that CANNOT be read, no matter what.

 

Bottom-line: not in XL/XE mode, maybe on Colleen mode.

[+Spancho]

Could the trigger pin be hard wired to the swap button pins from incognito, without causing damage to pokey?

[flashjazzcat]

5 minutes ago, Spancho said:

Could the trigger pin be hard wired to the swap button pins from incognito, without causing damage to pokey?

It's PIA, but that's more along the lines of what I was thinking. The button pin just needs pulling to ground; that will latch the button.

 

Actually reading the port instead of the latch in software is pointless anyway. You'd have to keep the trigger pressed at the exact moment the SIO is called after the software requests a disk change, and release it at precisely the correct moment so that multiple swaps don't occur. That's why the button is implemented as a latch. You set it, and it's acted on and cleared during the first subsequent SIO call.

Edited April 14, 2020 by flashjazzcat

[+Nezgar]

In software, you could look for some 'impossible' joystick direction, such as L+R or U+D, with an attached dongle with a button that creates that.

 

In hardware, maybe you could use some kind of AND (NOR?) logic gate that activates when both of two pins of an "impossible" direction are active, and then wire the output to the incognito button pin?

[_The Doctor__]

but please don't do the pin supersedes real joystick function, the tail of beta lyrae thanks you...

 

[Xebec]

Hmm I guess I was thinking that since Joy 3+4 aren't used in XL/XE mode - that there might be a possibility of an option in the BIOS that would 'read' the fire button of joystick 3 or 4 as the disk swap button?   no solder, modifications, or other changes required?    Turn it off if you didn't want it?

[StickJock]

Left & Right are paddle buttons, so you could see this combo with a pair of paddles plugged in.

Up & Down, I think, are driving controller pins.  The grey code is output onto these joystick pins.

 

So, both of these "impossible" directions are possible with standard equipment.

 

You could go with three simultaneous directions?  Say, L+U+R?

 

[flashjazzcat]

13 minutes ago, Xebec said:

Hmm I guess I was thinking that since Joy 3+4 aren't used in XL/XE mode - that there might be a possibility of an option in the BIOS that would 'read' the fire button of joystick 3 or 4 as the disk swap button?   no solder, modifications, or other changes required?    Turn it off if you didn't want it?

See post #5.

 

None of the suggested solutions provide a latched button, and there have been so many elegant and non-destructive options for creating the swap button (such as... the original one using the light conductor), I have to wonder why sub-optimal, kludgy solutions like these are necessary.

Edited April 14, 2020 by flashjazzcat
typo

[Xebec]

10 minutes ago, flashjazzcat said:

See post #5.

 

None of the suggested solutions provide a latched button, and there have been so many elegant and non-destructive options for creating the swap button (such as... the original one using the light conductor), I have to wonder why sub-optimal, kludgy solutions like these are necessary.

Re-read and got it now..  Thanks!   it'll basically flip back/forth too quickly between the disks without that ground is what i'm reading now..  and i'm guessing too complex to put something in software that says you can only change disk once per <time period>.  I appreciate the answers.     

[flashjazzcat]

11 minutes ago, Xebec said:

I appreciate the answers.

No problem. As I speculate: some means of pulling the button pin down via the joystick 3 or 4 trigger might get the job done (i.e. set the latch), but I did not yet delve into the 800 schematic to see whether this would be possible or prudent.