Eurotech Appliances VIPER / VIPER-LITE PXA255 - Manual (Page 57)

VIPER Technical Manual Detailed hardware description
© 2007 Eurotech Ltd Issue E 57
General purpose I/O
Eight general-purpose input lines and eight general-purpose output lines are provided
on connector PL9.
To read from IN[0:7], read the least significant byte located at offset 0x500000 from
CS5 (0x14000000) to sample the 8 inputs from PL9.
VIPER inputs PXA255 data
IN0 D0
IN1 D1
IN2 D2
IN3 D3
IN4 D4
IN5 D5
IN6 D6
IN7 D7
The PXA255 is not designed to interface to 8-bit peripherals, so when the 8-bits of data
are read only the least significant byte from the word contains the data.
Data bus
Most Significant Byte Least Significant Byte
D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
Don’t Care IN Data
PXA255 Transceiver PL9
D[0:7] IN[0:7]
3.3V
10k
ohms