[Coco] Trying to understand Cart Usage on Coco3

[RETRO Innovations]

On 8/23/2015 2:31 PM, Robert Gault wrote:
> RETRO Innovations wrote:
>> I am working on a small project that puts some EPROM in the cart 
>> port. I am
>> trying to test that the EPROM is in the right place, but I don't know 
>> how to
>> test via the Coco3 BASIC that the EPROM is there.  I've disconnected 
>> the CART
>> pin from Q on a std Typing Tutor Cart to so some testing, but I am 
>> not sure
>> where the addresses should be.
>>
>> Any help would be appreciated.
>>
>> Jim
>>
>
> Is the Cart plugged into the Coco3 cart port or an MPI?
>
> All Tandy Cart/Paks will have their ROMs addressed at $C000; same as 
> the Disk ROM. Your device will now not auto-start and you should be 
> seeing the Extended Basic message at turn on.
> To access the EPROM, assuming there is a program which starts at $0000 
> in the EPROM, just enter EXEC&HC000. Alternatively, you may be able to 
> get the EPROM to auto-start without using the CART line by having the 
> bytes in the EPROM at $0-1 = DK with the program start located at $0002.
Yeah, I don't want to *run* the code at that address, I just want to 
check that my code shows up in those addresses.

I pulled the CART/Q jumper so the autostart cart would not start on 
boot.  I then did a ?peek (49152), and I got 207, but the first byte of 
Typing Tutor is 204, and the number I get from peek (49152) is not 
consistent across boots.

Jim