Samsung SFD-321B specifications Input Signals, Density Select, Type Contents, Drive Select 0

FLOPPY DISK DRIVE SPECIFICATION

PAGE	17
MODEL	SFD-321B

5.3Input Signals

5.3.1Density Select

This siganl is used to distinguish between 1.6MB and 2MB Mode. The interface pin No.2 can be used as Density Select Input signal by attaching 0 Ω resistor onto "OPA" short plug when the High density media is inserted. The "HIGH" level designates 2MB Mode and the "LOW" level designates 1.6MB Mode. FDD can tell whether the inserted media is high or Low density by checking the signal coming from mechanical switch which detects the density selecting hole on the media.

	Type		Contents
	2 Mode	Automatic	Switching
	(2.0 / 1.0MB)	2.0MB : If High density media is inserted.
	(Non-connection of "OPA")
		1.0MB : If Low density media is inserted.
		Automatic Switching with "Density Select"
	3 Mode	2.0MB : If High density media is inserted
			with "Density Select" is "HIGH".
	(2.0 / 1.6 / 1.0MB)
		1.6MB : If High density media is inserted
	(Connection of "OPA")
			with "Density Select" is "LOW".
		1.0MB : If Low density media is inserted
			"Density Select" is not available.
5.3.2 Drive Select 0 and 1

Two trace plugs on the PCB, DS0 and DS1 are provided to select which Drive Select line will activate the interface signals for a unique drive in the daisy chain connection up to two drive units. Drive Select, when activated logical "LOW", enables all the I/O lines except Motor On line.

This signal also controls the lightening of In-Use LED.

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