Specifications

Chapter 4 Hardware Reference
ReadyBox Users Guide 35
Pin # Signal Description
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 Digital 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 Digital 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 Primary 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 Reserved Reserved
40 GND Digital Ground
41 +5V +5 volts +/-5%
42 +5V +5 volts +/-5%
43 GND Digital Ground
44 NC Not connected
Notes: The shaded area denotes power or ground. The signals marked with * = Negative true logic.