Re: ROM Dump of Amiga Keyboard controller

From: Greg King <>
Date: Fri, 27 Jun 2014 03:52:26 -0400
Message-id: <>
It seems to me that a "master, slave" microcontrollers model is the 
easiest method to implement.  You would use a fast master 
microcontroller with (at least) three I/O ports.  One master port would 
be connected to the (slow) slave's (MOS 6500/1) port C.  Another master 
port would be connected to another slave port.  One line from a third 
master port would generate the slave's clock signal.  And, two lines 
from that third port would control switches that feed 0V, 5V, and 10V to 
the slave's RESET line.

You don't need to bother with the slave's RAM; the master can dump the 
ROM directly.  It feeds a sequence of

     LDA $rom_address
     STA $port

instruction pairs to slave port C.  It increments the "rom_address" 
between each pair.  It toggles the RESET line between 5 and 10 volts at 
the appropriate cycles, so that the LDA can get its data from the mask 
ROM.  The master reads that data from its second port; and, stores the 
data in some place.

Syncronization is easy.  The master would know how many cycles are used 
by the 6500's reset sequence.  So, the master would know exactly when to 
feed the first opcode to port C.

       Message was sent through the cbm-hackers mailing list
Received on 2014-06-27 10:00:03

Archive generated by hypermail 2.2.0.