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:
31,248 Unformatted Bytes/Sector x 3
s = INT (--------) n = INT (--------------------------------)
where 31,248 = 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)
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 68 512 612
out out in 71 * 512 582 *
out in out 38 1024 1096
out in in 18 2244 2314
in out out 10 4096 4166
in out in 64 580 650
in in out 121 272 342
in in in 1 41,594 41,664
* 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)