Re: Lisa repair questions

On 08/12/2011 03:33 AM, tommoni wrote:
> Hi guys!
>
>> the cops chip is in the keyboard.
>
> no, definitively not!
>
> The Lisa keyboard does not have a COPS inside, but perhaps you think
> of something what we call a PRAM chip nowadays.

That's absolutely correct, the "PRAM" data is actually part of the 1K RAM that's seen by the both 6504 and the 68000 - so it's stored in the floppy controller, and backed up by the rechargeable battery pack when power is removed. When the Lisa is powered off, the RAM gets kept alive by the trickle part of the power supply.

The COPS controls power on/off, the keyboard, the mouse, and keeps the time and date. The COPS is also kept alive by the trickle voltage from the power supply. The power switch on the front of the Lisa is seen by the Lisa as part of the keyboard, but if the Lisa is off, the COPS sees this key press as a signal to turn the rest of the Lisa on.

The keyboard controller sends the keyboard ID when it's told to be reset, or when it's plugged in/powered on. This lets the Lisa boot ROM know what language to display. When an OS such as LOS boots, it's supposed to honor this ID and display language in that ID.

I don't remember off the top of my head, but I think I recall the Lisa HWG mention something about dip switches to set the language inside the keyboard. Of course, when you open up the keyboard, they don't exist. They're part of the ROM of the Intel microcontroller that scans the keyboard, etc.

HTH

-- 
-----
You received this message because you are a member of the LisaList group.
The group FAQ is at http://lowendmac.com/lists/lisa.html
To post to this group, send email to lisalist_at_email.domain.hidden
To leave this group, send email to lisalist+unsubscribe_at_email.domain.hidden
For more options, visit this group at http://groups.google.com/group/lisalist