I am looking for system programming information for a MS Permium
Softcard for the Apple 2e. Unlike the older Z80 Softcard, it does not
share main memory with the 6502. Also it does not have the same
mechanism to switch to 6502 subroutines as the original softcard did.
Instead it fits in the AUX slot and provides 80 col and 64K of Aux
RDR: and PUN: do work with an Apple Super Serial Card (SSC) in slot 2
but this is BDOS level access using functions 3 and 4. I would like to
be able to configure the SSC through software. I would also like to
port XMODEM to this card as I once did for the original softcard. On
the original softcard, it was a matter of changing to meomry mapped I/
O, setting up the proper mask bits and adjusting the addresses for the
way the z80 saw 6502 addresses.
The user's manual is particularly vague. It refers to a "System
Programmer's Manual". Also it says "Therefore it is not possible with
the SoftCard IIe version of CP/M to directly address Apple I/O memory
"The Z80 performs I/O through .... [the] ."6502 BIOS". There are 15
separate functions. All are accessed by storing information in a 7-
byte area located at 45-4B, and then performing a Z80 CALL instruction
to memory location 40. Information from the I/O system is returned to
the same 7-byte area."
I would expect to pass A,X,Y,PSW,SP,PC in those locations but that
seems not to be the case. The routine at 40H moves 80H to the I
register, then moves 00H to the I register, and returns.
I would appreciate any information on these I/O routines. It would
also be neat to be able to read my clock card, for example, from CP/M.
||9/27/2009 5:40:32 AM