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 RN11 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.
The Sector/Address Mark Found signal is used to send sector pulses to the controller. Sector pulses are derived from the servo disk. The number of sector pulses generated equals:
20,832 Unformatted Bytes/Sector x 3
s = INT (--------) n = INT (--------------------------------)
where 20,832 = frames derives from servo disk per revolution
s = number of sector pulses generated
INT = integer part of
n = the number of frames/sector (82 minimum)
One frame = 1/20,832 of a revolution.
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 82 512 594
out out in 83 * 512 584 *
out in out 44 1024 1105
out in in 22 2048 2209
in out out 11 4096 4419
in out in 58 768 839
in in out 149 256 326
in in in 1 48,538 48,608
* This is the default (factory installed) configuration,
and is recommended for PC/AT applications.
Frame Ground Option
A jumper at W28 is used to connect the drive's logic ground to its frame ground. The factory default configuration, which should be used for PC/AT applications, is a jumper installed at W28.
Jumper Frame ground connected to logic ground.
No Jumper Frame ground not connected to logic ground. (Default)