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NOTE: This does not mean that SWTBUG® is equipped with a binary loader-only certain
SWTPC binary tapes that contain a special binary loader (in ASCII) will work correctly.
To load the tape simply follow the instructions given for loading an ASCII tape, but keep the
reader locked on.
SPECIAL NOTES ON USING AN ACIA AND PROGRAM MODIFICATIONS
Many available 6800 programs written for MIKBUG® assume that a PIA type MP-C control
interface is being used and may address this port directly. When using an ACIA type interface,
these references need to be changed. For example, some programs, such as BASIC and
CORES, poll the PIA periodically to see if a character has been typed in. This is done in order to
kick out of a loop or a print sequence. (BASIC uses CTL..C. and CO-RES uses CTL..X.) The
source statements that do this usually take the following form:
B6 8004 LDA A PIAD LOAD A FROM DATA REG.
2B 03 BMI PRINT BRANCH IF NOT CHAR. SEEN
7E XX XX JMP READY or RESTART
PRINT REMAINDER OF SEQUENCE
To change to a MP-S serial interface, this code can sometimes be replaced as follows;
LDA A PIAD à ASR A SEE IF CHAR. LOADED
BMI PRINT à BCS PRINT BRANCH IF CHAR. INPUT
JMP READY
PRINT REMAINDER OF SEQUENCE
Before modifying any programs on your own, you should have a working knowledge of
SWTBUG'S ACIA input routine, ACIA operation, and your particular program. The following is a
list of patches to some SWTPC supplied programs.
BLKJAK - SWTPC 6800 Black Jack Program
LOCATION DATA
0270 7E 064A
0647 7E 026D
064A B6 E008
064D 27 08
064F B6 8004
0652 2B F3
0654 7E 0275
0657 B6 8004
065A 47
065B 24EA
065D 20 F5
With the above modifications BLKJAK will be compatible with either an ACIA or PIA type
interface.
CO-RES Ver. 1.0 and 1.01 ACIA Modifications
LOCATION DATA
1682 47
1683 24 02
1685 20 A0
BASIC 8K and 4K up to an including Ver. 2.0 cannot be modified for ACIA operation. Later
versions should be purchased.