micke@slaka.sirius.se (Mikael Karlsson) (10/25/89)
In article <4178@blake.acs.washington.edu> Dale Larson writes: >I do not recommend replacing your A500 keyboard with an A2000 keyboard. I don't share Dale's opinion. I certainly recommend replacing the keyboard. This is an article that I wrote two months ago but never got around to posting: ---------------------------------------------------------------------- Some time ago somebody asked if it was possible to connect an A2000 keyboard to an A500. Well, it is, sort of... Here's the story. Ins and outs (from the TECHREF manual): A2000 2 1 KCLK Keyboard clock __ _____ 5 4 2 KDAT Keyboard data | | \____ 3 NC ---> | | |____ 3 1 4 GND |__|_____/ 5 +5 6 SHIELD 6 A500 - from left to right when facing the machine (bus side to floppy side) 1 KDAT Keyboard data 2 KCLK Keyboard clock 3 RESET Reset signal (Hard wired) 4 +5 5 KEY Beats me 6 GND 7 STATW Power LED 8 INUSE Floppy LED Using this information I connected 2000 to 500; 1-2, 2-1, 4-6, 5-4. When I switched on I got a stream of (not acrid smoke :-) quotes. According to an earlier posting by George Robbins at CATS this meant that KDAT and KCLK were swapped. I changed my connections to: 1-1, 2-2, 4-6, 5-4. This time, no smoke, no quotes. So, I try to type something. Things look strange and after a couple of characters I get no output. Since I use conman (and VT100s) I try a Ctrl-Q. Ok, back in business. By now I can type almost anything, except "m", "n" and cursor keys. After a while I realise that these keys have some special meaning when used together with left and right amiga keys. I press and release left amiga and right amiga and finally everything works. So it seems like the A500 believes that the reset-keys are down. By pressing and releasing them one at a time I tell the A500 that they're up. The same thing happens if you try to reboot the A500 by pressing ctrl-amiga-amiga. What happens is that the A500 registers that the keys are pressed and then the keyboard resets itself leaving the A500 believing that the reset-keys are still down. Question: How does the A2000 detect a reset? Is there any HW involved? Is there a difference in the ROMs between the A500 and the A2000? Disclaimer: I take no responsibility at all for any damage made to your Amiga. Neither because of this fix or any other reason, such as earth quakes, tornados etc. Problems: You can't do a 3-finger reset. It doesn't matter much to me since I don't reboot often (twice a week maybe). Questions: Why did I have to swap KDAT and KCLK? Have I done anything wrong? Would it be possible to connect both keyboards at the same time? Would it be possible to connect a keyboard via the serial port? Where can I find a specification of the data sent from the keyboard? Comments? George? Dave? Last recommendation: I would feel much safer if you wait for somebody who knows what he's talking to acknowledge this before you start mutilating your Amiga 500 (and your friend's A2000 ;-). ---------------------------------------------------------------- Have fun. Mikael Karlsson, Lovsattersvagen 10, S-585 98 LINKOPING, SWEDEN micke@slaka.UUCP, micke@slaka.sirius.se {mcvax,munnari,seismo}!enea!liuida!slaka!micke C86.M-KARLSSON@LINUS.liu.se