[comp.sys.amiga.tech] Reading the Amiga OKI clock chip

deraadt@enme.UCalgary.CA (Theo de Raadt) (05/18/89)

I am in need of proper documentation for accessing the OKI chip on the
Amiga 2000 or 500. Looking in the A500/A2000 Technical Reference Manual,
I find some documentation on the chip, conflicting in some cases.

The section on the chip, says the base address is $dc0000. Looking at
the PAL equations a little later on in the book, I read that the
chip maps into $d80000 - $d8ffff. Nice going guys. Which is it?

It appears that the chip maps into long words, reading and writing the
lowest nybble of the word. Is this right? Ie. register 5 is at
base_address + 5*4.. right?

What is this that I read about overlap between the custom graphics
chip registers and the RTC? If the chip is at $d80000 - $d8ffff then
there is no overlap, is there? Or do the graphics chips go down below
$dff000 much?

This is for Minix.. and also so that I can write a little program for
myself to clear the test and stop bits - I hate when that happens and
the clock does not work; that is what the problem is, right?

Enough "right?" for tonight...
 <tdr.
Theo A. de Raadt - CPSC student
Calgary, Alberta, Canada