6502/cc65
1
0
Fork 0
mirror of https://github.com/cc65/cc65.git synced 2024-06-07 23:29:39 +00:00
Code Issues Projects Releases Wiki Activity

Make sure not to load ACIA driver on IIgs' Z8530

Browse Source 
The Pascal Firmware Protocol Bytes ID are not enough to differentiate an SSC card from a IIgs serial firmware:
http://www.1000bit.it/support/manuali/apple/technotes/misc/tn.misc.08.html

Loading a2(e).ssc.ser on a IIgs succeeds, then goes to limbo when one tries to use the serial port.

Check first byte on the slot's firmware in addition to the four existing ones, as it's supposed to be $2C (BIT instruction) on an SSC card, and $EF (65C816 SEP instruction) on the IIgs' serial firmware (ROM revisions 0, 1, 3).
This commit is contained in:
Colin Leroy-Mira 2023-09-10 21:13:27 +02:00 committed by Oliver Schmidt
parent 043590c971
commit 38f7daf40e
1 changed files with 21 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
libsrc/apple2/ser/a2.ssc.s
View File

@ -132,16 +132,33 @@ ParityTable:
.byte $60 ; SER_PAR_EVEN
.byte $A0 ; SER_PAR_MARK
.byte $E0 ; SER_PAR_SPACE
; (*): The first byte we'll check at offset 0 is
; expected to be a BIT instruction on any Apple2
; machine with an ACIA 6551, including the //c
; and //c+.
; The IIgs, on the other hand, has a
; Zilog Z8530 chip and its firmware starts with
; a SEP instruction. We don't want to load this
; driver on the IIgs' serial port.
;
; The next four bytes we check are the Pascal
; Firmware Protocol Bytes that identify a
; serial card.
IdOfsTable:
.byte $00 ; First instruction
.byte $05 ; Pascal 1.0 ID byte
.byte $07 ; Pascal 1.0 ID byte
.byte $0B ; Pascal 1.1 generic signature byte
.byte $0C ; Device signature byte
IdValTable:
.byte $38 ; Fixed
.byte $18 ; Fixed
.byte $01 ; Fixed
.byte $31 ; Serial or parallel I/O card type 1
.byte $2C ; BIT
.byte $38 ; ID Byte 0 (from Pascal 1.0), fixed
.byte $18 ; ID Byte 1 (from Pascal 1.0), fixed
.byte $01 ; Generic signature for Pascal 1.1, fixed
.byte $31 ; Device signature byte (serial or
; parallel I/O card type 1)
IdTableLen = * - IdValTable