ROM Dump of Amiga Keyboard controller

From: Gerrit Heitsch <*gerrit_at_laosinh.s.bawue.de*> Date: Mon, 09 Jun 2014 13:02:01 +0200 Message-ID: <53959429.2050706@laosinh.s.bawue.de> · gerrit_at_laosinh.s.bawue.de

Hello,

has anyone here ever done a ROM dump of the keyboard controller of the 
Amiga?

The controller is, on most Amigas, a 6570-036. This one looks a lot like 
the 6500/1 Microcontroller MOS offered back then. It's, of course, based 
on the 6502 that's why I thought it appropriate to ask here.

Datasheet here:

http://www.6502.org/documents/datasheets/mos/mos_6500-1_one-chip_microcomputer_oct_1986.pdf

This Microcontroller has a test feature where you supply +10V to the 
RESET pin and from then on all memory fetches happen not from the 
internal ROM but from Port PC. According to the datasheet this will 
allow you to load a small program into the internal RAM (64 Bytes) that 
can, once RESET returns to +5V, dump the ROM to another port.

Anyone here ever built such a circuit? Writing the program would be 
interesting since you have no address lines but only have to make sure 
that the correct byte is present on Port PC in the next cycle (external 
clock is divided by 2).

  Gerrit

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