Configuration and Jumper Options
Drive Address Selection
The Drive Address jumpers are identified as DA1, DA2, and DA3. ID selection is binary, as shown here. The ESDI controller's documentation will specify the drive address to use.
Drive Select Jumpers
Address DA3 DA2 DA1
1 out out in
2 out in out
3 out in in
4 in out out
5 in out in
6 in in out
7 in in in
"Drive Address 0" (no jumper at DA1, DA2, or DA3)
is a "deselect" (i.e., no drive selected).
For many multiple drive installation, each drive must have a unique address. An exception is that for every drive in a PC/AT installation, verify that the only Drive Address jumper is at DA2; move the jumper if necessary
(the special twisted interface cable that is generally used takes care of addigning a unique address to each drive). PC/AT controllers can typically support a maximum of two drives.
The Interface Terminator factory installed at RN1 provides proper termination for the interfacelines. When daisy-chaining multiple drives, leave the terminator installed only in the last physical drive on the daisy-chain cable; remove the terminator from each of the other drives. In most PC/AT applications, the C: drive is actually at the end of the cable and should retain the terminator
W5 controls the spindle option. If W5 is installed, the drive waits for a Start Spindle command (after power is applied) to start the spindle motor.
If W5 is not installed (the factory default configuration), the drive automatically starts the spindle motor at power-on. W5 is not installed for PC/AT applications.
W1 selects the sectoring mode. If W1 is installed, the drive operates in the soft-sectored mode.
If W1 is not installed (the factory default configuration), the drive operates in the the hard-sectored mode. W1 is not installed for PC/AT applications.
The number of bytes per sector may be specified using the Set Bytes Per Sector command or by selecting a default sector configuration with jumpers W2, W3, and W4 as follows:
Jumpers Sectors Bytes/Sector
W4 W3 W2 Formatted Unformatted
out out out 53 512 588 *
out out in 54 512 576
out in out 28 1024 1116
out in in 14 2048 2232
in out out 7 4096 4464
in out in (Reserved)
in in out 97 256 321
in in in 1 31,248 31,248
* This is the default (factory installed) configuration,
and is recommended for PC/AT applications.
Frame Ground Option
(This option only applies to Rev B and higher boards.) A jumper at W28 connects logic ground to frame ground. A jumper would normally not be installed for PC/AT applications.