This information is from the OSS bulletin board (408-446-3451).


 The Official Procedure:

 To Turn a SuperCart OFF:

 1> Close I/O Channel 0

 2> Wait for the LSB of RTCLOK ($14) to change value.

 3> Do an SEI

 4> Save $AFFF ... this is the 'cart status' register ... you'll need
it if you wish to restore the cart

 5> STA $D508.  This turns the cart OFF.

 6> Poke $3FA(GINTLK), 0 to tell the OS that there is no cart
installed.

 7> Poke $6A(RAMTOP),$C0 to tell OS that full RAM is available.

 8> Do a CLI

 9> Open #0,12,0,"E:"


 To Turn a Supercartridge back ON:

 1> Perform steps 1-3 from above.

 2> LDX with 'cart status' value saved in step 4 above.

 3> STA $D500,X. This turns cart ON

 4> Poke $3FA,1 to tell OS that there
   is a cart.

 5> Poke $6A,$A0 to tell OS that less   RAM is available.

 6> Perform steps 8-9 from above.



 Notes:

 These should be obvious, but if you're a space case like me...

 The ON/OFF code MUST be 'safe'. That is, if RAM resident, it should
not be overwritten by any application you may be running, whether
under Cart control or not. (Especially the $AFFF value if you'll want
to turn the cart back on!) Disk .COM files are a viable alternative.

 Once the cart is off, there MUST be a program IN PLACE to take over
control of the computer! That may be DOS or it might be your own
code.

 Depending on exactly what you're doing, some sort of RESET handler
might prove useful.

 Again depending on application, XL/XE users may want to add PORTB
manipulations.