Re: A83: Port Protocol


Re: A83: Port Protocol

``In a message dated 12/30/99 9:27:02 AM Central Standard Time, writes:

> Just wondering, does anybody have any information about the low-level port 
> protocol for accessing flash ROM on the TI-83 plus? I've been setting port 
> breakpoints under VTI and it seems to be port 14h, otherwise the problem is 
> that VTI doesn't implement 83p flash ROM and keeps crashing.
>  Solignac Julien
>  Cygnus X-1 Technologies
> - ICQ 38240788

You're that guy who made ICE huh? Well, I'm reluctant to reply to you, but 
since no one else has answered the question yet, I figured "what the hell"... 
First of all, I dont beleive that VTI emulates the ports correctly, and I 
dont think VTI can archive things correctly either. In the Emulator, 
everything is essentially RAM, and when you go through the process of 
archiving a Var on VTI, the FreeRam goes up, but the Archive Mem doesnt 
change, then exiting the Memory Manager and coming back to it later will 
produce an error. So Im saying dont rely on VTI to uncover system info for 
you, cuz it doesnt work the same as the calcs... Anyways, on the 83+, Ports 6 
and 7 controls the Memory Slots. Port 6 controls the page that gets swapped 
into $4000-$7FFF, and Port 7 controls the page that gets swapped into 
$8000-$BFFF. I think you can manually change the page by outputting a new 
value through those ports, and having the System Interrupt enabled should 
take care of the process to swap them... Im not sure if doing this is very 
safe though, and if youre looking for a way for "ICE" to use the archive 
memory, its best if you work with some of those Undocumented System Routines, 
which handle the archiving/unarchving more safely, cya. =)