"Optional" circuits listed in the A1200 schematics

[LoadWB]

Yes, I'm browsing schematics again.  This time I'm looking over the A1200 to find information on the clock port.  While doing this, I have found a couple of things that I question.

Firstly, there's the ever-told warning not to un/plug joysticks or mouse while the computer is powered on because of potential damage to the CIAs (8520.)  According to the schematics, these ports are not only intercepted by another TTL, but also seem to be converted into a data stream?

Second, optional Flash Memory?!  Could this be used to hold a working Kickstart image?

Then, the chance for a 68881 on the mobo?

And were any models made with on-board RTC (shown as optional in the schematics)?

I'm also digging up information on the 68HC05 used as the keyboard MPU.  This is a programmable unit which apparently contains ROM or some kind of programmable ROM (just downloaded the info from Freescale.)  That could be useful for some projects.  Is there any information on its existing program?

[EDIT] My mobo (can't see the version, I think it's 1D4) does not have a small clock port.  It does have a header on P9B, and just solder points for P9A, which are labeled in the schematics as "memory expansion."  Now, I seem to recognize the lower part of P9B as being a clock port; it has A2-5, D16-23, _reset, _iowr/rd, _rtc_cs (real time clock chip select, I assume,) _pwr_bad (interesting...) _spare_cs, and _int6.  Am I correct here?  Also, where does this expanded memory get mapped?

[rkauer]

 C= never maded a single 1200 with FPU, nor RTC...

 The schematics are right, but do you want to mess with one 1200 mobo? Chances are you'll fry something...

[LoadWB]

rkauer wrote:
 C= never maded a single 1200 with FPU, nor RTC...

Figured as much.

The schematics are right, but do you want to mess with one 1200 mobo? Chances are you'll fry something...

Yes.

[nBit7]

I'm also digging up information on the 68HC05 used as the keyboard MPU. This is a programmable unit which apparently contains ROM or some kind of programmable ROM (just downloaded the info from Freescale.) That could be useful for some projects. Is there any information on its existing program?

The 68HC05 is a very nice MCU to program for.  Much nicer instruction set than PICs and AVRs that are so popular now.  However they tended to be OTP (one time programmable) or UV erasable.  Flash versions tended to be much more expensive.  
I don't think you will find the sourcecode for the keyboard controller.

[potis21]

but you *could* find schematics on aminet for bypassing that controller and installing a PS/2 keyboard by builtind your own. There is of course some lack of compatibility (the A keys)but an external controller is the way to go if you are up to seriously expand your amiga. But there is a way to do it without a soldering iron - you could commercially obtain a controller.

Anyway, amiga is sort of primitive implementation of "user foolproof design" today found on most computers (i.e. Static protection, buffered ports, psu overload protection, short-circuit protention) therefore if you really love your amiga DON't mess with it with no reason.

[Matt_H]

C= never maded a single 1200 with FPU, nor RTC...

They came close, though. The manual says the FPU is a factory-installed option.

@ LoadWB

Yeah, the Flash memory part looks interesting... but it seems like the traces for it never made it into the PCB layout. I wonder if that module was supposed to connect to the "complete" dual-44-pin clockport headers. There was also supposed to be a 1MB version board with the second meg of Chip RAM connecting there... maybe the Flash was part of that module.

If you have the full header on P9B, your board is probably much older than 1D4. I have a 1D1 that still only has the clockport pins rather than the full headers.

A full service manual would help, I think. I've never seen one for a 1200, but the 3000T version has a complete list of all components.

[Doobrey]

LoadWB wrote:

Second, optional Flash Memory?!  Could this be used to hold a working Kickstart image?

In theory, kind of maybe..
The /Flash chip select is only available on the expansion connector or Gayle, IIRC it was really meant for a 'diagnostic ROM'(ie developer/repair use).

You still need the normal Kickstarts installed, since they contain the code to check for and use the code in the flash.

Edit: Oops, forgot to mention, if you're mad enough to try it, you've gotta change the first word of the ROM image from $1114 to $1111 otherwise exec won't recognise it as valid ROM.

Another problem is that the same address space is used by BlizzardPPC/Cyberstorm boards for their ROMs.

It does have a header on P9B, and just solder points for P9A, which are labeled in the schematics as "memory expansion."
..
Also, where does this expanded memory get mapped?

It's not much use, it was meant as an extra 1MB of Chip RAM.
 The A1200 was planned to ship with 1MB of Chip, and those headers were for an upgrade to bring it upto 2MB.