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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: DILA65 on February 27, 2005, 03:07:08 AM

Title: Need help with external 1200 keyboard wiring
Post by: DILA65 on February 27, 2005, 03:07:08 AM

I am going nuts trying to get a keyboard working. I followed directions I found on Aminet and ended up with apostrophes flying across the screen, after some hunting I learned that this means the clock and data lines are reversed. I switched the lines and the flying punctuation stopped but there is no response from the keyboard. Keyboard works perfectly on a 3000, so what did I do wrong. HELP

thanks

   

Title: Re: Need help with external 1200 keyboard wiring
Post by: RedskullDC on February 27, 2005, 05:12:49 AM

Quote

DILA65 wrote:
I am going nuts trying to get a keyboard working. I followed directions I found on Aminet and ended up with apostrophes flying across the screen, after some hunting I learned that this means the clock and data lines are reversed. I switched the lines and the flying punctuation stopped but there is no response from the keyboard. Keyboard works perfectly on a 3000, so what did I do wrong. HELP

thanks

Hi,

Can you give us a bit more information?
Which directions did you follow on Aminet?

/hard/hack/a500key1.lha  is probably the easiest to follow, even though it is written in Spanish. Requires a couple of trace cuts on the under side of the board, which is preferable to mangling the legs of your PLCC chips which some of the other mods advocate.

If you are getting the continuous stream of ''''''''s then
the power and ground signals must be connected ok.
Double check that you have indeed swapped CLK and DATA, because it should just work from where you were with the '''''''''''s.

Red

Title: Re: Need help with external 1200 keyboard wiring
Post by: Castellen on February 27, 2005, 05:41:38 AM

The same thing can happen if the keyboard data line is not connected.
Or possibly if the A1200 keyboard microcontroller is not disconnected from the data line, making the external keyboard connect in parallel.

It'd be a lot tidier to just remove the keyboard micro, U13, if you know someone with a SMD rework tool.

It's then just a matter of connecting 5V, ground, KB clock and KB data to the external keyboard and you're in buisness.

Here's a schematic of the keyboard circuit:
http://amiga.serveftp.net/Schematics/A1200_schematics/JPEG/A1200-KeyboardMPU.jpg

(Sorry for the long URL)

Title: Re: Need help with external 1200 keyboard wiring
Post by: DILA65 on February 27, 2005, 08:24:03 PM

Thanks for the schematic, this shows another error in the aminet files. On aminet I found files that said to use pin 42,43 on U7 and never mentioned lifting pins on U13, another that said use pins 43,44 on U7 nothing about U13, one that said 43,44 on U7 lift 12,13 on U13. The schematic shows 13,14 on U13 as the data and clock signals. At present I am using 43,44 on U7 with pins 13,14 lifted on U13 and get no response from keyboard, if I swap the data and clock lines at the keyboard din connector I get contiunuous apostrophes. I think tomorrow I am going to order an interface.    :-?

Title: Re: Need help with external 1200 keyboard wiring
Post by: Stedy on February 27, 2005, 11:38:36 PM

Hi,

If you have a Rev 2B motherboard, take a look at this:
http://main.aminet.net/hard/hack/A1k2-KEYB.lha (http://main.aminet.net/hard/hack/A1k2-KEYB.lha)
it makes installing an adaptor much easier, it did for me.

Ian