Specifications

Chapter 3 Hardware
LittleBoard 800 Reference Manual 39
Pin # Signal Description
47 SD8 Secondary Disk Data 8 – Refer to SD3 on pin-2 for more information.
48 SD9 Secondary Disk Data 9 – Refer to SD3 on pin-2 for more information.
49 SD10 Secondary Disk Data 10 – Refer to SD3 on pin-2 for more information.
50 GND Ground
Notes: The shaded area denotes power or ground. The signals marked with * = Negative true logic.
Floppy Drive Interface (J17)
The LPC47B272 chip provides the floppy controller and supports one floppy drive as configured. The
floppy signals are provided through the standard 34-pin connector (J17). This connector is separate (not
shared with) from the parallel port connector (J16). The floppy controller will support a 360k, 720k,
1.2M, 1.44M, or 2.88M drive.
The floppy drive connector has 34 pins, 2 rows, odd/even, (1, 2) with 0.100” pin spacing.
Table 3-12. Floppy Drive Interface Pin/Signal Descriptions (J17)
Pin # Signal Description
2 DRVEN0 Drive (Floppy) Density Select 0
4 NC Not connected
6 DRVEN0 Drive (Floppy) Density Select 0
8 INDEX Index – Sense to detect that the head is positioned over the beginning of a track
10 MTR0 Motor Control 0 – Select motor on drive 0.
12 NC Not Connected (DS1)
14 DS0 Drive Select 0 – Select drive 0.
16 NC Not Connected (MTR1)
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.
29 NC Not Connected (NC1)
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)
33 NC Not Connected (NC2)
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,
9, 11, 13,
15, 17,
19, 21,
23, 25,
27, 31
GND Ground
Notes: The shaded area denotes power or ground. The signals marked with * = Negative true logic.