From: The FLEX User's Group =
has=20
documentation on the FLEX disk operating system for the 6800 and =
6809. A great tool for developing new software for FLEX is Michael =
Evenson's=20
SWTPC 6800/6809 Emulator. I used this emulator to update all of my =
FLEX=20
utilities and the software below. I have written a Windows Help file =
based on=20
the 6809 FLEX Users Guide but I have added some information on the 6800=20
version. FLEX =
OnLine Help=20
(ZIP 32k) The SWTPC MF-68 floppy disk system used a DC-1 or DC-2 controller =
card and=20
single-sided 35-track To modify FLEX 2 to use 40 or 80 tracks the NEWDISK command must be =
changed=20
to format more Modifyin=
g=20
SWTPC 6800 FLEX 2 for the DC5 (PDF 49k) Disk =
Drivers Source=20
Double Sided (TXT 6K) Newdisk =
Source=20
Doubel Sided (TXT 15k) The floppy disk boot code in SWTBUG doesn't work as well as it =
should. (A few=20
more bytes would have made it solid.) Here is a better boot =
loader. From your terminal emulator; press L to start a S1 download, then =
send this=20
text file. The program starts at memory address 0300. Back in 1981 I disassembled the I/O and disk drivers for TSC FLEX 2.0 =
for=20
SWTPC 6800 and added comments based on the 6809 FLEX Adaptation Guide. I =
also=20
disassembled the NEWDISK program. I have compared the listing to the =
binaries=20
and they seem to match byte for byte. Disk =
Drivers Source=20
(TXT 6K) I created a floppy disk controller debugger that will read and write =
sectors=20
and load a FLEX binary file. It can be in RAM or ROM. This version =
supports a=20
double sided and is for a controller with a DRQ / IRQ status register. =
This=20
includes the DC-3, DC-4, DDC16, or my DC-5.
=20
Modifying SWTPC 6800 FLEX 2
5.25-inch disk drives. SWTPC FLEX 2 was written =
for=20
this system. This version will work with a 5.25-inch
double-sided =
40-track=20
drive (IBM 360K) but it will only use one side and 35 tracks. It will =
even work=20
the
720K 3.5 inch drives.
tracks. The existing FLEX 2 will read the number of =
tracks=20
from the formatted disk and use all of the space.
To modify FLEX 2 to =
read=20
double-sided drives the disk driver routines must be changed in addition =
to=20
the
NEWDISK command.Boot Loader Program
Boot Loader =
Source=20
Code
S1 Format Boot=20
LoaderOriginal Source Code
DiskBug
J
xxxx
Jump to location xxxx
M
xxxx
Examine and alter memory =
location
N
Examine next memory =
location
V
Examine same memory =
location
B
Examine previous memory =
location
Z
xx
Select and restore drive xx to =
track=20
0
T
ttss
Read sector ss on track tt into =
BUFFER and=20
display it
L
ttss
Load binary file starting at =
track tt and=20
sector ss. Display transfer address.
W
ttss
Write BUFFER into sector ss on =
track=20
tt
$
Return to =
SWTBUG
The source code is identical for both the 6800 and 6809 versions, = just the=20 hardware addresses change.
This 6800 version is located at $C000 so it can go in an EPROM on the = MP-A2=20 CPU board. Use the SWTBUG Z command to jump to this monitor.
DiskBug = $C000=20 Monitor Source (PDF 23K)
DiskBug = $C000=20 Monitor Source (TXT 14K)
DiskBug = $C000=20 Monitor S1 file (TXT 2K)
This 6809 version is located at $F000 so it can go in an EPROM or a = RAM on=20 the MP-09 CPU board.
DiskBug = $F000=20 Monitor Source (PDF 24K)
DiskBug = $F000=20 Monitor Source (TXT 14K)
DiskBug = $F000=20 Monitor S1 file (TXT 2K)
I fixed the DIR and Date utilites so they work with dates past = 1999.