Commodore 1581 - Appendix A: Changing the Device Number

APPENDIX A
CHANGING THE DEVICE NUMBER
Two switches on the back of the 1581 enable you to change the
device # of the drive. You can use a screwdriver, pen, or any other
small tool to set the switches. The following table shows the settings
required for each device number:
Left
UP
DOWN
UP
DOWN
Right
UP
UP
DOWN
DOWN
Device #
8
9
10
11
Another way to temporarily change the device number of a disk
drive is via a program. When power is first turned on, the drive reads
an I/O location whose value is controlled by the two switches on its
circuit board, and writes the device number it reads there into mem
ory locations 119 and 120. Any time thereafter, you may write over that
device number with a new one, which will be effective until it is
changed again, or the 1581 is reset.
FORMAT FOR TEMPORARILY CHANGING THE DISK DEVICE NUMBER:
PRINT#15,"U0>" + CHR$(n)
Where n = 8 to 30
EXAMPLE:
Here is a program that sets any device number:
5 INPUT "OLD DEVICE NUMBER"; ODV
10 INPUT "NEW DEVICE NUMBER"; DV
20 IF DV<8 or DV>30 then 10
30 OPEN 15,ODV,15, "U0>" + CHR$(DV): CLOSE 15
-NOTE
If you will be using two disk drives, and want to tempo
rarily change the device number of one, you will need to
run the above program with the disk drive whose device
number is not to be changed turned off. After the program
has been run, you may turn that drive back on. If you need
to connect more than two drives at once, you will need to
use the hardware method of changing device numbers.
Ill