perholm@daimi.UUCP (Per Holm) (09/01/86)
From perholm Mon Sep 1 02:40:26 MET DST 1986
Article 628 of net.micro.cbm:
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Path: daimi!perholm
>From: perholm@daimi.UUCP (Per Holm)
Newsgroups: net.micro.cbm
Subject: z80 cardridge for cbm64
Message-ID: <366@daimi.UUCP>
Date: Mon, 1-Sep-86 00:20:21 GMT
Article-I.D.: daimi.366
Posted: Mon Sep 1 02:20:21 1986
Date-Received: Mon, 1-Sep-86 00:20:21 GMT
Reply-To: perholm@daimi.UUCP (Per Holm)
Distribution: %D
Organization: DAIMI: Dept. of Comp. Sc., Univ. of Aarhus, Denmark
Lines: 46
Summary:
I have some problems vith my z80 cardridge for the c64. It will not work
as it should. It seems that there is some problems sharing the memory the
VIC chip. It seams that the z80 and the vic chip uses the address bus at the
same time, because i get updated my screen on wrong locations with this
small test program......( A modification from c64 reference guide).
6510 boot program...
$8000 lda #$7f ; turn 6510 irq's off
$8002 sta $dc0d
$8005 lda #$00 ; turn z80 on
$8007 sta $de00
$800a nop ; never used...
z80 program (will never stop)
$0000 00 nop ; turn on time for the z80
$0001 00 nop
$0002 00 nop
$0003 21 03 f5 ld hl,f503 ; screen location
$0006 34 inc (hl) ; increment screen location
$0007 c3 03 00 jmp 0003 ; do loop.....
the z80 program uses z80 addresses for 6510 addresses add $1000
to start the program do type 'sys4096*8'
My problem is that the wrong spots changes on the screen sometimes.
Does anyone know how to get it work as it should ?? then plaese give me some
hints.
I have a cp/m users guide for the cardridge but it seems that the scematic
diagram is missing..(it is mentioned in chapter 6) does anyone know where
to get one ? ... Commodore in Denmark can't help me..
I am missing some pages in the back of the manual about a relocator (2/80)
which should be on the pages 173 to 184 in the first edition, first printing
and it seems that this program has been dropped in a latter printing.
Per Holm