Path: utzoo!attcan!uunet!cbmvax!fred
From: fred@cbmvax.UUCP (Fred Bowen)
Newsgroups: comp.sys.cbm
Subject: Re: Another info request for old CBM computers
Message-ID: <5745@cbmvax.UUCP>
Date: 20 Jan 89 16:11:23 GMT
References: <2035@iitmax.IIT.EDU> <448@csd4.milw.wisc.edu> <2748@mibte.UUCP> <3549@utastro.UUCP>
Reply-To: fred@cbmvax.UUCP (Fred Bowen)
Organization: Commodore Technology, West Chester, PA
Lines: 42

In article <3549@utastro.UUCP> sjk@utastro.UUCP (Scot Kleinman) writes:
>Regarding some 8096 questions.  I have a SuperPET, and I believe the 
>8096 banking is done the same way. You can activate 4k at a time through
>either $9000 or $a000 (I'm almost sure it's $9000). There are a few pokes
>which activate any of the given banks through that window [...]
>
>Regarding the speaker, yes it does play music (well sort of).  There are
>two memory locations which control it [...]
>
>Regarding the RS-232 interface.  I believe a few companies used to make IEEE to 
>RS-232 interfaces [...]

The SuperPET bank switching is done through a register located at $EFFC,
into which you place the bank number (0-15).  There are 16 4K RAM banks which
which appear in memory at $9000-$9FFF.  There are other RAM and ROM expansion
cartridges which appear at $A000.

There is also a system latch, located at $EFF8, used to select the CPU (6502
or 6809), write protect memory, etc.  When accessing the system latch, bit 7
of the bank select register must be set and the toggle switch on the side of
the SuperPET must be set to PROG.

Sound is generated on the SuperPET the same way it is on the  PET and 8032,
using the CB2 output on the user port.  I/O (VIA) location $E84A sets the
timbre, and the magical values are 15, 31, and 51.  Location $E848 sets the
note.  Place values in these registers, then enable the shift register/
oscillator by placing the value 16 into location $E84B.  Disable sound by
placing a zero there.

The SuperPET has two built-in ACIA's, a 6551 at location $EFF0 and a 6850 at
location $EFF4.  The 6551 is used for RS-232 I/O, the 6850 was simply a high
speed serial line.  A standard RS232 connector is included.  I don't know of
any IEEE-RS232 interfaces, but I do know IEEE-Centronics interfaces are still
available.

--
-- 
Fred Bowen			uucp:	{uunet|rutgers|pyramid}!cbmvax!fred
				arpa:	cbmvax!fred@uunet.uu.net
				tele:	215 431-9100

Commodore Electronics, Ltd.,  1200 Wilson Drive,  West Chester,  PA,  19380