Micropolis 1550-Series


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 adding a unique address to each drive). PC/AT controllers can typically support a maximum of two drives. Interface Termination 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
Spindle Control 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.
Sectoring 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	   35		512		595
out	out	in	   36		512		578 *
out	in	out	   19		1024		1096
out	in	in	    9		2048		2314
in	out	out	    5		4096		4166
in	out	in	   32		512		651
in	in	out	   64		256		325
in	in	in	    1		20,832		20,832

* This is the default (factory installed) configuration, 
  and is recommended for PC/AT applications.