Specifications

Chapter 3 Hardware
ReadyBoard 800 Reference Manual 31
Pin # Signal Description
23 PDIOW* Primary Device 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 PDIOR*
Primary 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 PDIORDY Primary 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 PDCEL Primary Cable Select – Used to configure IDE drives as device 0 or device 1
using a special cable.
29 PDDACK* Primary DMA Channel Acknowledge – Used by the host to acknowledge data
has been accepted or data is available. Used in response to DMARQ asserted.
30 GND Ground
31 IRQ14 Interrupt Request 14 – 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 PDA1 Primary IDE ATA Disk Address (0 to 2) – Used to indicate which byte in the
ATA command block or control block is being accessed
34 PD33/66 UDMA 33/66 Sense – Senses which DMA mode to use for IDE devices.
35 PDA0 Primary IDE ATA Disk Address (0 to 2) – Used to indicate which byte in the
ATA command block or control block is being accessed
36 PDA2
Primary IDE ATA Disk Address (0 to 2) – Used to indicate which byte in the
ATA command block or control block is being accessed
37 PDCS1* Primary Slave/Master Chip Select 1 – Used to select the host-accessible
Command Block Register.
38 PDCS3* Primary Slave/Master Chip Select 3 – Used to select the host-accessible
Command Block Register.
39 IDE LED IDE Activity – Indicates IDE drive activity to yellow IDE LED (D5) on card
edge.
40 GND Ground
41 +5V +5 volts +/-5%
42 +5V +5 volts +/-5%
43 GND Ground
44 NC Not connected
Notes: The shaded area denotes power or ground. The signals marked with * = Negative true logic.