This page is useful if you plan replacing the original
disk drive of the MSX with a new PC disk drive. As you know the
Philips VG8235
came with a 360kb floppy disk drive - and by just building a 34 to 14
pin cable interface adaptor and fitting in the new drive you'll still only
be able to use 360kb. To add 720kb floppy disk support you'll need to replace
the disk ROM for another that has this support.
If you just want to replace the disk without adding support
for 720kb disks you just have to build a 34 to 14
pin cable interface. Follow these tables for this and be sure to read more about
changing a drive on a NMS8245 computer here. NOTE:
My tables refer to the VG8235/20 model - the tables in the previous site refer
to the NMS8245 computer - the cable is similar but the connections are different
- don't get mixed up. The details about opening up the computer and installing
the new drive are valid for both nevertheless.
| PC DISK DRIVE |
| 1 |
- |
| 2 |
READY |
| 3 |
- |
| 4 |
IN USE/OPEN |
| 5 |
- |
| 6 |
DRIVE SELECT 3 |
| 7 |
- |
| 8 |
INDEX |
| 9 |
- |
| 10 |
DRIVE SELECT 0 |
| 11 |
- |
| 12 |
DRIVE SELECT 1 |
| 13 |
- |
| 14 |
DRIVE SELECT 2 |
| 15 |
- |
| 16 |
MOTOR ON |
| 17 |
- |
| 18 |
DIR |
| 19 |
- |
| 20 |
STEP |
| 21 |
- |
| 22 |
WRITE DATA |
| 23 |
- |
| 24 |
WRITE GATE |
| 25 |
- |
| 26 |
TRACK00 |
| 27 |
- |
| 28 |
WRITE PROTECT |
| 29 |
- |
| 30 |
READ DATA |
| 31 |
- |
| 32 |
SIDE SELECT |
| 33 |
- |
| 34 |
READY |
| - |
GND |
|
| VG 8235/20 |
| 1 |
INDEX |
| 2 |
DIR |
| 3 |
STEP |
| 4 |
WRITE DATA |
| 5 |
WRITE GATE |
| 6 |
DRIVE SELECT 0 |
| 7 |
DRIVE SELECT 1 |
| 8 |
DRIVE SELECT 2 |
| 9 |
DRIVE SELECT 3 |
| 10 |
MOTOR ON |
| 11 |
- |
| 12 |
TRACK00 |
| 13 |
WRITE PROTECT |
| 14 |
READ DATA |
|
| CONNECTIONS |
PC |
MSX |
| 8 |
1 |
| 18 |
2 |
| 20 |
3 |
| 22 |
4 |
| 24 |
5 |
| 10 |
6 |
| 12 |
7 |
| 14 |
8 |
| 6 |
9 |
| 16 |
10 |
| GND |
11 |
| 26 |
12 |
| 28 |
13 |
| 30 |
14 |
|
|
| CONNECTIONS |
PC |
MSX |
| 4 |
2 (b) |
| 6 |
9 |
| 8 |
1 |
| 10 |
6 |
| 12 |
7 |
| 14 |
8 |
| 16 |
10 |
| 18 |
2 |
| 20 |
3 |
| 22 |
4 |
| 24 |
5 |
| 26 |
12 |
| 28 |
13 |
| 30 |
14 |
32 |
13 (b) |
GND |
11 |
|
|
For 720kb support on the VG3235/20 you have two options:
-You can fit in a Philips NMS8245 ROM and practice your soldering
skills a bit. Check information on how to do this here.
Be warned that this page refers an unspecified VG8235 series model (might be
a series 00, 20, etc). You might want to cross-reference the given connections
using the service
manuals. Many thanks to Graw for giving me a spare 8245 disk ROM! Follow
my VG8235/20 connection tables and build a 34 to 14 pin cable adaptor to connect
the new PC floppy disk drive to the internal disk connector.
-You can buy a new ROM ( with additional memory looking +
fast disk rom) from Bas
Kornalijnslijper (homepage here )
and get it to replace the original disk ROM.
Finally connect the drive to the external b-connector using a normal 34 to
34 pin
flat ribbon
cable.
The
easiest
solution.
|
The ribbon cable connected to the MSX external disk drive connector. |
I hope you find this page useful. Feel free to contact me
if you have questions.
"MSX" is a trademark of the MSX
Association
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