[Coco] [Color Computer] Multi-Pak Question

[John Eric]

which is why i made my mod switchable - Jeric




________________________________
From: Bob Devries <devries.bob at gmail.com>
To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
Sent: Friday, January 30, 2009 5:33:28 PM
Subject: Re: [Coco] [Color Computer] Multi-Pak Question

Robert Gault said:
> Upgrading the multi-pak for Coco3 use will in no way cause a problem with Coco1 or Coco2 use. These upgrades are completely safe regards backwards compatibility.

Actually, that is not quite true. Yes, the modicication will not adversly affect the coco 1 or 2, but there is at least one PAK which will not work with that mod in place. I refer to the original CocoMax joystick controller cartridge. It's address range is right in the address range that is excluded by the modification for the Multi-Pak.

--
Regards, Bob Devries, Dalby, Queensland, Australia

Isaiah 50:4 The sovereign Lord has given me
the capacity to be his spokesman,
so that I know how to help the weary.

website: http://www.home.gil.com.au/~bdevasl
my blog: http://bdevries.invigorated.org/

----- Original Message ----- From: "Robert Gault" <robert.gault at worldnet.att.net>
To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
Sent: Saturday, January 31, 2009 8:55 AM
Subject: Re: [Coco] [Color Computer] Multi-Pak Question


> seanrussoct08 wrote:
>> Hi all coco-ers!
>> 
>> I have a quick question.  I have a multi-pak 26-3124 that i bought off
>> of Ebay a few years ago and haven't used it much.  I had a friend several years ago tell me that he thought you could use
>> one of these multi-paks to access more than one device at a time, but
>> i didn't think you could.  Could someone settle this for me? and if
>> yes, how do you?
>> 
>> 2nd, if i buy the hardware from cloud9 to convert this to a coco3
>> capable multi-pak, will it never work on my coco2 again?
>> 
>> Thanks,
>> 
> 
> Upgrading the multi-pak for Coco3 use will in no way cause a problem with Coco1 or Coco2 use. These upgrades are completely safe regards backwards compatibility.
> 
> My guess is that when you bought the unit you did not receive the user's manual. Because if you had read the manual, you would see that not only can you select the active slot by using the switch on the unit but also by POKEing a value to 65407 aka &HFF7F.
> The manual states to use the following values:
>  Selected slot      Value
>   1                $00
>   2                $11
>   3                $22
>   4                $33
> A more detailed explanation that supplied by the manual follows. The slots are actually numbered with base-0 notation; 0-3. The nominal value used is the slot value for both the msn and lsn nibbled of the byte, thus $00, $11, $22, $33.
> Actually there are two functions being controlled by the value. The msn selects ROM available to the Coco at $C000-$DFFF, while the lsn selects the I/O device responding to $FF40-$FF5F.
> It is not necessary to use the same value for both msn and lsn. So if you had a device (ex. RealTimeClock) in slot 1 and your disk controller in slot 4, you could POKE &HFF7F,&H30 and retain the Disk ROM in slot 4 while doing I/O through slot 1.
> This also means you could read a ROM in an auto-starting pak without starting the pak. Select the slot of the ROM pak using the msn while keeping the lsn at the default 3.
> 
> Doing the above is a bit more complex. You would want to use a short ml program and be sure to clear the CART interrupt before returning to Basic.
> 
> --
> Coco mailing list
> Coco at maltedmedia.com
> http://five.pairlist.net/mailman/listinfo/coco 


--
Coco mailing list
Coco at maltedmedia.com
http://five.pairlist.net/mailman/listinfo/coco