Ampro Corporation Single Board Computer Littleboard 550 User Manual
Page 44
Chapter 3
Hardware
38
Reference Manual
LittleBoard 550
Pin #
Signal
Description
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.
34
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.
35
SDA0
Secondary Disk Address 0 – Refer to SDA1 on pin-33 for more information.
36
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.
38
SDCS3#
Secondary Slave/Master Chip Select 3 – Used to select the host-accessible
Command Block Register.
39
Reserved
Reserved
40
GND
Ground
Notes: The shaded area denotes power or ground. The signals marked with * = Negative true logic.