Path: utzoo!mnetor!uunet!husc6!uwvax!dogie!uwmcsd1!ig!agate!ucbvax!pro-angmar.UUCP!tmetro
From: tmetro@pro-angmar.UUCP (Tom Metro)
Newsgroups: comp.sys.apple
Subject: Apple //c Resets
Message-ID: <8804200757.AA17542@crash.cts.com>
Date: 20 Apr 88 00:13:27 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Reply-To: pnet01!pro-angmar!tmetro@nosc.MIL
Organization: The Internet
Lines: 19


I read an article that explained how you could copy the ROM code at $D000 to
$F800 into the Bank Switched RAM on a //e. This then allowed you to modify
vectors that are at the top of the address space, such as RESET, IRQ and NMI.
I tried this on my //c. I was able to copy the ROM code, verify that I had
copied it, modify the code, and verify my modifications. The modification I
tried was to redirect the RESET vector, but it wouldn't work. I verified that
I had the Bank Switched RAM selected for read operations by looking at the
status of $C011 and $C012. The RESET still caused a normal reset and left the
//c with the ROMs selected and the RAM turned off. 
 
Does anyone know if the hardware that controls the bank switching on a //c
gets reset with the RESET signal?
It must not on a //e for this to work...
Is the $D000-$FFFF bank switched RAM contained on the motherboard of the //e?
This article gave me the impression that it was located on a card, but maybe
that refers to an unenhanced //e.
 
Thanks.