Author Topic: PCW 8xxx that has problem with keyboard signal  (Read 546 times)

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Offline michomis

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PCW 8xxx that has problem with keyboard signal
« on: 19:37, 31 March 18 »
I have recieved PCW 8xxx series without keyboard.
I do not know how computer should work without keyboard, but it shows, or press itself, random  keys on CPM for example. I have constructed and connected PCW-IO module from http://www.habisoft.com/pcwwiki/doku.php?id=en:hardware:perifericos:pcw-io and connected PS/2 keyboard, and as for video output and reset line it works fine, but it still shows random keys on screen. No responce from pressing any key. 3 LEDs on PS2 keyboard light up at computer start. Only once, it worked, which means, I could type any tekst. I am pretty sure that keyboard works, so it must be something on PCW board.
Schematics shows, that CLK and DATA lines from keyboard socket goes through 74HC14 chip, and then to 40028 ASIC. So maybe they are faulty? Any ideas?
Oh, and I have put new solderings on ASIC and 74HC14, but with no effect.
Board look fine to me.

Offline GeoffB17

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Re: PCW 8xxx that has problem with keyboard signal
« Reply #1 on: 23:30, 31 March 18 »
Do note that the working of the PCW keyboard is quite different from any PC keyboard.

See the page of info (fairly technical, VERY detailed) from John Elliot, at:

http://www.seasip.info/Unix/Joyce/pcwkbd.html

for full info about the PCW keyboards.

Note, PCW keyboards are available, from business supplier in UK, for not too bad a price.   Prob more with postage to Poland.   Use google search for cjemicros and PCW Amstrad and you should find it.

No doubt it IS possible to use a PC keyboard, but you'd need an extra level of interface to convert the scancodes from the PC device into something that the PCW could use, and it might NOT be worth the trouble?   However, John Elliots info noted above could provide the detail you need to implement such an interface?

To what extent Habi's IO device implements this conversion, I don't know.   Hopefully JE's data will help you test things.

Geoff
« Last Edit: 23:37, 31 March 18 by GeoffB17 »

Offline michomis

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Re: PCW 8xxx that has problem with keyboard signal
« Reply #2 on: 22:31, 01 April 18 »

No doubt it IS possible to use a PC keyboard, but you'd need an extra level of interface to convert the scancodes from the PC device into something that the PCW could use, and it might NOT be worth the trouble?   However, John Elliots info noted above could provide the detail you need to implement such an interface?

To what extent Habi's IO device implements this conversion, I don't know.   Hopefully JE's data will help you test things.

Thank you for respond. The thing is I have already made two of those PCW-IO modules, and they seem to work fine with PC PS/2 keyboard, but with one exeption. Those keyboards do not always "ON" correctly. Now I have been sitting with this problem through all evening, and I found out that after power on of PCW, 3 leds on keyboard flash once. After that, one led (num lock) should stay light, and after that keyboard work almost always fine, if not - keyboard do not respond at all. Problem is I have to turn power on and off many times untill it snaps. It seems I need to turn it off and on like 10-20 times, to get keyboard in working state (with num lock on).
I have tested two PS/2 keyboard. Problem is still there. Problem with timings? Bad soldering? PCW chips?
Please check my video:
https://youtu.be/0KYKEVSuirs

Offline Habi

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Re: PCW 8xxx that has problem with keyboard signal
« Reply #3 on: 01:04, 30 April 18 »
Hi.

I've seen that behaviour before twice. In one case it was a very noise / unstable power supply (which doesn’t seem to be the case), in the other the culprit was the programmer (a TOP3000 IIRC) which didn’t write correctly the fuses on the 16F628A.

There are fuses for brown-out protection and power-up timer, which should be both disabled. If the keyboard microcontroller boot first that the one on the PCW-IO the handshake would be lost. I have tested a PicKit 2, a PicKit 3 and several Wellon programmers and those programmed the PIC right.

Could you check the configuration word of your PIC, please? Perhaps we have the same case here.

Regards.

Offline michomis

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Re: PCW 8xxx that has problem with keyboard signal
« Reply #4 on: 10:28, 04 May 18 »

There are fuses for brown-out protection and power-up timer, which should be both disabled.
Could you check the configuration word of your PIC, please? Perhaps we have the same case here.


Thanks for respond. First of all I have borrowed Top3000 programmer ver5.02.
It seems to programm pic correctly - it do not show any errors. Anyway I have checked sum for your prueba.hex and it is different with this what was loaded on chip...

As for config settings here is what I can set during programming (attachment).

Should I set them manually? How then?


Offline Habi

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Re: PCW 8xxx that has problem with keyboard signal
« Reply #5 on: 14:01, 06 May 18 »
I think there is a bug on that software; for starters, the oscillator should be the internal RC plus IO. But on the other hand, it shouldn’t work at all with the LP option, which is not your case. I think the interface is ignoring bit 4 of the configuration word, which should be $2118, but also something has to be wrong in the writing process if the hex files differ.
For reference, this is what appears on my Wellon programmer:

And my PicKit 2:

Could you try another programmer?
I’m thinking also to make a firmware that doesn’t hang if it doesn’t detect a keyboard, but instead send blindly a reset command to the keyboard and start the detection again. I’ll give it a try.

Offline michomis

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Re: PCW 8xxx that has problem with keyboard signal
« Reply #6 on: 14:12, 07 May 18 »

Could you try another programmer?
I’m thinking also to make a firmware that doesn’t hang if it doesn’t detect a keyboard, but instead send blindly a reset command to the keyboard and start the detection again. I’ll give it a try.

I will try to use another programmer, but it can take couple weeks. I do not own it my self.
As for updated hex file, it would be great idea to try it.

Offline michomis

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Re: PCW 8xxx that has problem with keyboard signal
« Reply #7 on: 10:45, 30 May 18 »
After using programmer TL866CS, it seems to work in 95% of cases, which is great improvment. It is not fully working, but quite good progress.Only problem now is, I cannot use mouse (for example in DeskJoy). When I use PS/2 splitter - keyboard works fine (but only in mouse port!!!), mouse do not work at all in both ports.

Offline Habi

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Re: PCW 8xxx that has problem with keyboard signal
« Reply #8 on: 10:17, 03 June 18 »
I'm glad it works better now. :)


Please, take care with splitters; there are different standards unfortunately. I use same pinout at the PS/2 connector as a ZX-Uno, for reference.