Ampro Corporation Littleboard 550 manual Floppy Drive Interface J14

Chapter 3 Hardware

Floppy Drive Interface (J14)

The VT82C686B chip provides the floppy controller and supports two floppy drives. The floppy signals are provided through the standard 34-pin connector (J14).

The floppy controller will support the 360k, 720k, 1.2M, 1.44M, and 2.88M drives. USB floppy disk drives are also supported.

Table 3-12. Floppy Drive Interface Pin/Signal Descriptions (J14)

Pin #	Signal		Description
2	DRVEN0		Drive (Floppy) Density Select 0
4	NC		Not connected
6	NC		Not connected (DRATE0)
8	INDEX		Index – Sense to detect that the head is positioned over the beginning of a track
10	MTR0		Motor Control 0 – Select drive motor 0.
12	DS1		Drive Select 1 – Select drive 1.
14	DS0		Drive Select 0 – Select drive 0.
16	MTR1		Motor Control 1 – Select drive motor 1.
18	DIR		Direction – Direction of head movement (0 = inward motion, 1 = outward motion).
20	STEP		Step – Low pulse for each track-to-track movement of the head.
22	WDATA		Write Data – Encoded data to the drive for write operations.
24	WGATE		Write Gate – Signal to the drive to enable current flow in the write head.
26	TRK0		Track 0 – Sense detects the head is positioned over track 0.
28	WRTPRT		Write Protect – Senses the diskette is write protected.
30	RDATA		Read Data – Raw serial bit stream from the drive for read operations.
32	HDSEL		Head Select – Selects the side for Read/Write operations (0 = side 1, 1 = side 0)
34	DSKCHG		Disk Change – Senses the drive door is open or the diskette has been changed
			since the last drive selection.
1, 3, 5, 7,		GND	Ground
9, 11, 13,
15, 17, 19,
21, 23, 25,
27, 29, 31,
33

Notes: The shaded area denotes power or ground. The signals marked with * = Negative true logic.

LittleBoard 550 Reference Manual 41