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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: Tahoe on January 06, 2005, 10:57:05 AM
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I have an Elbox tower with keyboard interface. Felling smart I hooked up my DELL PS/2 keyboard to it using a purple DIN/PS2 adapter that came with a Lite-On keyboard. Now here is the thing, it partially works.
The whole rows of keys QWERTY and ASDFG work, but the bottom row doesn't. So no ZXCVB for me, no Space. Numbers do not work but the number pad does work. Regular Enter doesn't work, the one on the number pad does. Could this be the converter only works right with a Lite-on board it came with? I believe these same things used to come with Logitech boards as well.
Unfortunatly I haven't been able to find a real DIN keyboard yet. :(
Also I want to buy a PS/2 mouse converter. Will this work with a Logitech Optical Mouse (mx310) which comes with a USB>PS2 converter?
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Also I want to buy a PS/2 mouse converter. Will this work with a Logitech Optical Mouse (mx310) which comes with a USB>PS2 converter?
Yes, it will. I tried both a Logitech Wheel Mouse Optical and the same one but cordless on all available converters (TopolinoIII, EZMouse, Cocolino) and they all worked.
However, none of the converters works on KVM switches (I tried two).
Bye,
Thomas
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@Tahoe
Very untypical for a converter/amiga failure, it's more likely a keyboard one. Do the same keys fail on other keyboards (either ps/2 or at)?
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I don't have another keyboard laying around.... And obviously forgot to mention: The board works fine on my PC :(
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Although it is very untypical for a keyboard converter, I could imagine that it is a damage or a loose contact.
Usually the key codes are transmitted from the keyboard to the motherboard through a serial connection. So the only conversion the converter has to do is to translate PC/2 key codes into Amiga key codes and convert PS/2 transmission protocol into serial transmission protocol.
However, AFAIK on the A1200 all the electronics for decoding key presses are on the motherboard and the serial connection happens internally. So for the A1200 the converter has to do more. It has to translate the key codes back into matrix combinations. So if some of the matrix lines are connected loosely, a whole row of keys won't work.
Bye,
Thomas
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@Thomas:
Well... you could be right, never mind actually :)
The A1200 motherboard have the input for matrix keyboard. Matrix connected to microcontroller placed on the MB (a plcc44 quadratic chip with (M) [motorola] logo). It converts matrix keystrokes further to the amiga serial keyboard protocol, which then goes to the 8520 chip serial port.
There are 2 ways connecting external at=ps/2 keyboard converters - to the matrix instead of real keyboard, the converter then must emulate keypresses, OR to the serial pins of either keyboard controller or 8520 chip (because the serial interface is open-collector and permits parallel connecting of several controllers).
In the second case, no such effect could emerge, in the first case it is quite likely.
The advice is to check, clear, reconnect the cable which should be connected in place of original A1200 keyboard (if any).