Specifications

Chapter 3 Hardware
36 Reference Manual LittleBoard 800
Pin # Signal Description
10 SDD11 Secondary Disk Data 11 – These signals (0 to 15) provide the disk data signals.
11 SDD3 Secondary Disk Data 3 – These signals (0 to 15) provide the disk data signals.
12 SD12 Secondary Disk Data 12 – These signals (0 to 15) provide the disk data signals.
13 SDD2 Secondary Disk Data 2 – These signals (0 to 15) provide the disk data signals.
14 SDD13 Secondary Disk Data 13 – These signals (0 to 15) provide the disk data signals.
15 SDD1 Secondary Disk Data 1 – These signals (0 to 15) provide the disk data signals.
16 SDD14 Secondary Disk Data 14 – These signals (0 to 15) provide the disk data signals.
17 SDD0 Secondary Disk Data 0 – These signals (0 to 15) provide the disk data signals.
18 SDD15 Secondary Disk Data 15 – These signals (0 to 15) provide the disk data signals.
19 GND Ground
20 NC/Key Not Connected - Key pin plug
21 SDDREQ Secondary DMA Channel Request – Used for DMA transfers between host and
drive (direction of transfer controlled by DIOR* and DIOW*). Also used in an
asynchronous mode with DMACK*. Drive asserts IDRQ0 when ready to
transfer or receive data.
22 GND Ground
23 SDIOW* Secondary I/O Read/Write Strobe – Strobe signal for write functions. Negative
edge enables data from a register or data port of the drive onto the host data bus.
Positive edge latches data at the host.
24 GND Ground
25 SDIOR* Secondary I/O Read/Write Strobe – Strobe signal for read functions. Negative
edge enables data from a register or data port of the drive onto the host data bus.
Positive edge latches data at the host.
26 GND Ground
27 SIORDY
Secondary I/O Channel Ready – When negated extends the host transfer cycle
of any host register access when the drive is not ready to respond to a data
transfer request. High impedance if asserted.
28 CSEL Not connected
29 SDACK* Secondary Cable Select – Used to configure IDE drives as device 0 or device 1
using a special cable
30 GND Ground
31 IRQ15 Interrupt Request 15 – Asserted by drive when it has pending interrupt (PIO
transfer of data to or from the drive to the host).
32 NC Not connected
33 SDA1 Secondary IDE ATA Disk Address 1 – Used (0 to 2) to indicate which byte in
the ATA command block or control block is being accessed
34 SPDIAG UDMA 33/66 Sense – Senses which DMA mode to use for IDE devices.
35 SDA0 Secondary IDE ATA Disk Address 0 – Used (0 to 2) to indicate which byte in
the ATA command block or control block is being accessed
36 SDA2 Secondary IDE ATA Disk Address 2 – Used (0 to 2) to indicate which byte in
the ATA command block or control block is being accessed
37 SDCS1
Secondary Slave/Master Chip Select 1 – Used to select the host-accessible
Command Block Register.