Enhancing my A600 Portable part I: touchpad AND mouse connected/switchable

[Photon]

See attached pic.

Right now, I have a Cocolino inside it, soldered onto the joyport pins, and using a touchpad for navigating menus.

However, now I'd like to make it possible to use the A600 in DPaint, too

But since the Cocolino is connected inside, I can't really just 'plug in a mouse' in the mouse port, can I?

I guess my options are:
- mount a female PS/2 connector in the case and a switch for the +5V to either the mouse inserted into that connector, or the touchpad. Is that enough though?
- unsolder the Cocolino from the mouse port internally, solder on a female 9-pin dsub, and plug that into an automatic mouse/joy switcher thingy I bought a while back (says 'MAUS JOYSTICK remote control' on the front)
- mount a switch for 'some of the mouse port pins' (which ones?) so I can allow an external Amiga mouse to be inserted.


There are some advantages to each, I like the second alternative because it means no more holes in the case and also allows a joystick. But it's one more item I have to fasten up and fit inside.

If the first alternative is possible, it has the advantage that I can plug in an optical mouse without using a SECOND Cocolino. So anyone know if it's okay to keep the signal pins connected to both as long as power only goes to one of them?

[Zetr0]

@photon

you will need to provide a proper +5v if you want to split the coco between a touch-pad / mouse

the amp output on the joyport is not enough for much more than a coco and a low-power ps2 mouse.

so provide it a proper +5v, remember to run some return limmitation or you will cook paula and the CIA chips.

personally in my approach i would buffer the signals from the joyport and run the coco off that (including a different +5v and ground rail) - you can then keep the joyport as a dedicated joyport (or amiga mouse in times of desperate need)

[Photon]

Thx for answering Zetr0.

I'm not adding mouse support just to stick something in in times of desperate need, if I insert a mouse it will be the best mouse possible. The whole purpose is to be able to draw properly in DPaint.

Buffering is out, run some return limitation says nothing to me, and I'm definitely looking for a simple way to hook it up.

Certainly the +5V to the mouse port is ample, I've run an MS IM Explorer 3.0 via a PS/2 converter, a Cocolino, a joy/mouse switcher and 1M of cable to my A500-040 with SCSI interface all on a 36W PSU for almost 2 years.



You mean if I have a 2-pole switch that either send +5V and GND to the touchpad, or +5V and GND to the mouse, I still risk cooking a chip?

I'd think it was safer this way as the switch would be on the 'mouse' side of the Cocolino electronics.

[Zetr0]

@photon

sorry chap, been rushing a bit today, getting stuff done so I have my workshop / office back -

okay... here is the info to what i was babbling about earlier

The Amiga Joyport can only supply 50mA MAX, thats to say driving a joystick and low-power mouse (via roboshifter) should be okay, BUT a capacitive touch-pad will draw a whole lot more -

Let me say that my MS Optical mouse (about 4/5 years old now) draws 100mA, where as basic ball mouse will be a little over a 25mA - a capacative touch pad will need atleast what the MS mouse requires... I have tried to find some sources but i cannot a the moment.

do you see where this is going ?

if you draw to much power it will damage the return as it pulses the signal back- ie Paula or one of the CIA's

although a swich isolates current draw (should that another device be plugged in) it wont protect the IC's should any one device attempt to pull to much current.

I would suggest you need to do two things.

Increase the current of the +5v

limmit the return through the use of capacitor(s), you will need to do a little math, I will try and come up with a simple protection circuit so you can run more mA yet safe guard the Chips.

in the mean time.... if you want to save princess paula and reach level six... get some reading in =)

[Zetr0]

Additional

I did some research, the PC PS2 mouse port provides 275mA - this is over 5 times what the Amiga outputs.

I would try and discover how much current is needed for the touch pad your gonna use photie, although these capacative touch pads use a PS2 protocall they most likely going to require a fair sum of juice.

I picked up some white papers from synaptics, its a good place to start to give you an idea, worse case scenario you could just email them.

[Photon]

I actually thought the +5V was output directly. But multimeter proved otherwise, 1.2 Ohm from floppy power to a 74xx chip, 6.5 Ohm to joyport pin.

How big a load a PC PS/2 port is not directly relevant, and I've looked at four difference models and makes of mice and they all say 100mA. Now I doubt they all draw as much, since one is a laser mouse with added logic for sideways scrolling and another is one of those small notebook mice. It's much more likely they've specified a generic current draw that it will safely not exceed.

Mildly interesting, bottom line is that I will simply connect the switch to the normal +5V and ground with a cap across, directly to the mouse/touchpad and disconnect those pins on the PS/2 connector from the Cocolino.

But I must say it's surprising if it's as damaging as you say. Both the touchpad and misc. mice have been used (via Cocolino) in both my A500 and A600 for years on a daily basis, without a single missed mouse-move.

My touchpad is a Cirque Easy Cat PS/2, and there are no electrical specification for it anywhere, nor pictures of the little sticker on the back. I bet it says '5V 100 mA'

[Cammy]

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[Mellonhead]

@photon

Good to see more portable A600 projects! What type of display is that?

-hl

[Photon]

It's the Joytech 8" (?) screen for the PS2 slim, bought from gameseek.co.uk. Apparently Joytech have been bought up, and I can't see them available anywhere, let me know if they are. I haven't actually called Gameseek up and asked, but...

They're very nice with proper RGB input and one of the few LCDs that can also handle PAL and interlace perfectly. No scaling artifacts. They've exaggerated the contrast, but certainly in games they look very good. Going to Germany in spring and a guy will swap the EEPROM to fix it.

I'd think it would be a lot easier to find LCDs for NTSC Mellonhead? Just take any that support svideo or RGB (or VGA via Indivision ECS) and go? Unless the purpose is to run PAL stuff ofc.

Cammy, on PC, USB has advantages, but on Amiga you have to load a driver and USB latency is greater than PS/2 latency, maybe even greater on a 68000 machine. I have zero need for a numpad. Otherwise it would have been a way to not have to solder, but an expensive one for a worse result and I would still have to open the Amiga and make a hole in the chassis.


At the moment I'm leaning towards combining the +5V mod above with internalizing the mouse/joy switcher, as that would also allow two joysticks. Depends on how easy it is to find & mount a PS/2 connector, and whether I can fit & mount the switcher easily inside.

[Cammy]

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