[Coco] [Color Computer] Multi-Pak Question

[Neil Morrison]

There's a manual on http://coco_docs.tripod.com/id51.htm

Neil

----- Original Message ----- 
From: "Robert Gault" <robert.gault at worldnet.att.net>

> 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.
>
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