[Coco] [Bulk] Re: AT306 Mouse and Keyboard

[Joel Ewy]

So it looks like the three pins labeled "Mouse" aren't a mouse port at
all, but jumpers to select between two different functions, or to select
whether a mouse or keyboard is connected to the port -- or perhaps
whether the connector you have your keyboard hooked up to is connected
to the mouse port or the keyboard port.  That would certainly explain
why there are only three pins.  I'd say you are probably on pretty safe
ground just putting a jumper on those two pins, if running it that way
suddenly makes the keyboard work.

As for keys being buffered, the keyboard has a microcontroller in it
which I believe can buffer keystrokes.  The keyboard is all powered up
and working, but unable to send scancodes to the computer until you
jumper the pins that attach its data and/or clock line to the Super I/O
chip.  Then the communication lines open up and the keyboard's
controller can send all the buffered keystrokes.  Or something like that.

JCE

Paul Fitch wrote:
>  
>   
>> The layout diagram in the AT306 manual shows the MDAT and 
>> MCLK lines coming off the SuperIO chip, but the lines just 
>> end.  No terminaion or grounds, or anything.
>>
>> I pulled the data sheet off the web for the PC87303 IAT VUL 
>> that is on the motherboard.  The KBDAT is connected to pins 
>> 95 and 141 of the SuperIO chip.
>> The KBCLK is connected to pins 96 and 4.  The MDAT is 
>> connected to pins 94 and 142, and MCLK is connected to pins 
>> 93 and 3.  The RTC is on pins 8-10.
>> I don't have a big enough magnifying glass (the eyes are 
>> going) to see any damage to the traces coming off the chip in 
>> the area of pins 3-10.
>>
>> Still, after further play, I'm sure the problem is somewhere 
>> along in there for the following reasons:
>>
>> 1) the Kernal error said it couldn't start the RTC, not that 
>> the time was wrong.  
>>
>> 2) The keyboards (AT with full size connector and the PS/2 to 
>> AT converter) both showed the numberlock light on bootup.  
>> That tells me that the keyboard is getting its + and - power. 
>>  The only two lines remaining are the KBDAT and KBCLK. 
>>
>> Question for all:  Would the RTC fail to keep any time at all 
>> if the battery was dead?  And if theres no internal clock, 
>> would that affect the KBCLK signal?
>>
>> I made a mistake earlier, the CR2025 is a 3v lithium not 5v 
>> like I originally thought (please refer to eyes going bad 
>> statement above).  Anyone know if a CR2032 (which is the same 
>> form factor) could be used in its place.
>> I don't want to do any damage I can avoid, but I'm thinking 
>> my problem with the keyboard could be traced to a dead RTC battery?
>>
>>     
>
> Progress of a sort.  I put the CR2032 in the RTC battery holder and
> attempted to boot the machine.  It still claims that it failed to start the
> clock.  Then I get the logon prompt, and again, no keyboard response.  I'm
> tapping keys and just getting frustrated.
>
> So then my muse speaks to me, and I take a small screw driver and drag it
> across the the three pins labeled mouse (remember this header is located
> just south of the SuperIO chip) with me calling PIN 1 the closest to the
> chip, and PIN 3 the farthest.  When the screw driver connects PINS 1 and 2,
> a bunch of characters shows up on the line I was trying to type on.  Holding
> the screw driver across PINS 1 and 2, I can type.  Take it off, and I see
> nothing, put it back on, and the characters I just typed suddenly appear.
>
> I then took a smallalligator clip and placed it across PINS 1 and 2, and
> proceeded to logon to the machine as SUPER.  I'm now logged on.
>
> So my question is, what are the odds of me doing permenant damage to this
> machine if I place a jumper block across PINS 1 and 2 of the MOUSE header?
> As stated above, the SuperIO chips lines for the mouse don't appear to be
> terminated, and there are only two of them, so it looks like I'm shorting
> MCLK across MDAT. 
>
> Why would that apparently unclog the keyboard buffer?  Because if those keys
> weren't being buffered, I wouldn't see them when the two pins were shorted.
>
> I want to put a jumper block across those two pins and reboot and see if
> that allows the RTC to work as well. 
>
>
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