[Coco] AT306 Mouse and Keyboard

[Christopher Hawks]

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. 

	Nope. My AT306 has complained about not starting the clock for years, but, the 
keyboard works fine.

-- 
Christopher R. Hawks
HAWKSoft
---------------------------------------------------------
"Give a man fire and he's warm for a day, but set fire to him and he's
warm for the rest of his life"