Ampro Corporation Littleboard 550 用户手册

38

Reference Manual

LittleBoard 550

33

SDA1

Secondary Disk Address 1 – One of three signals (0 – 2) used to indicate which
byte in the ATA command block or control block is being accessed.

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SD33_66

UDMA 33/66 Sense – Used to detect the presence of an 80 conductor IDE cable
on the secondary IDE channel.  Enables BIOS to sense which DMA mode to
use for IDE devices.

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SDA0

Secondary Disk Address 0 – Refer to SDA1 on pin-33 for more information.

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SDA2

Secondary Disk Address 2 – Refer to SDA1 on pin-33 for more information.

37

SDCS1#

Secondary Slave/Master Chip Select 1 – Used to select the host-accessible
Command Block Register.

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SDCS3#

Secondary Slave/Master Chip Select 3 – Used to select the host-accessible
Command Block Register.

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Reserved

Reserved

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GND

Ground

Notes: The shaded area denotes power or ground.  The signals marked with * = Negative true logic.