Ampro Little Board 700, Reference Manual

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Chapter 3 Hardware
38 Reference Manual LittleBoard 700
Floppy Drive Interface (J14)
The VT82C686B chip provides the floppy controller and supports two floppy drives. The floppy signals
are provided through the 26-pin connector (J14).
The floppy controller will support the 360k, 720k, 1.2M, 1.44M, or 2.88M drives
Table 3-12. Floppy Drive Interface Pin/Signal Descriptions (J14)
Pin # Signal Description
1 KEY
2 DRVEN0 Drive (Floppy) Density Select 0
3 GND Digital Ground
4 INDEX Index – Sense to detect that the head is positioned over the beginning of a track
5 GND Digital Ground
6 MTR0 Motor Control 0 – Select motor on drive 0.
7 GND Digital Ground
8 DS1 Drive Select 1 – Select drive 1.
9 GND Digital Ground
10 DS0 Drive Select 0 – Select drive 0.
11 MTR1 Motor Control 1 – Select motor on drive 1.
12 DIR Direction – Direction of head movement (0 = inward motion, 1 = outward
motion).
13 GND Digital Ground
14 STEP Step – Low pulse for each track-to-track movement of the head.
15 WDATA Write Data – Encoded data to the drive for write operations.
16 WGATE Write Gate – Signal to the drive to enable current flow in the write head.
17 GND Digital Ground
18 TRK0 Track 0 – Sense detects the head is positioned over track 0.
19 GND Digital Ground
20 WRTPRT Write Protect – Senses the diskette is write protected.
21 GND Digital Ground
22 RDATA Read Data – Raw serial bit stream from the drive for read operations.
23 GND Digital Ground
24 HDSEL Head Select – Selects the side for Read/Write operations (0 = side 1, 1 = side 0)
25 GND Digital Ground
26 DSKCHG Disk Change – Senses the drive door is open or the diskette has been changed
since the last drive selection.
Notes:
The shaded area denotes power or ground. The signals marked with * = Negative true logic.