[Coco] Detecting carts

Bill Pierce ooogalapasooo at aol.com
Thu Jul 5 10:45:12 EDT 2012

Thanks Mr Gault,... didn't think of just reading the ports, This may work with others as well, as they are all on different addresses. I think the Midi paks do something similar when they are in the ready state. I'll do some peeks and pokes. The Orchestra 90 pak will probably be the oddball as you can write to it at any time. It always seems to be open. But you never know.

Thansk again

Music from the Tandy/Radio Shack Color Computer 2 & 3 
Bill Pierce
ooogalapasooo at aol.com

-----Original Message-----
From: Robert Gault <robert.gault at att.net>
To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
Sent: Thu, Jul 5, 2012 2:37 am
Subject: Re: [Coco] Detecting carts

Bill Pierce wrote:

 Hi guys,
   Anyone know of an easy way in "C" (or M/L sub) to detect the presence of 
ertain catridges?

 RS Speech & Sound pak.
No idea about most of the paks but this should work with the Speech Sound pak as 
long as no other pak does the same thing.
Two I/O bytes are used with this pak, $FF7D and $FF7E. The latter is used to 
end data to the pak and when read shows the status of the pak. If $FF7E bit 7 
msb) is 0, the pak is busy processing a command.
ith a Coco3 and MPI, $FF7E (for me) is 255 without a S&S pak and does not 
hange when POKEd. With a pak present, the following happens.
The manual says, "... you should first monitor the status byte to determine 
hether or not the S/SC is ready to accept another character."
ikewise if the status bit is always high after sending a value to $FF7E, you 
hould not have an S/SC in the system. The converse result might be a false 

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