NuDAQ ACL-7120A, User Manual

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Programming
4.2 Digital I/O Programming
The ACL 7120A provides 32 digital input channels and 32 digital output
channels. Four I/O port address (Base+0, ..., Base+3) are reserved for these
digital I/O channels. The relationship between I/O address and I/O channels
are specified as following:
** Digital Input Register Format:
Address: BASE + 0, BASE + 1, BASE + 2, BASE + 3
Attribute: Read for digital input
Data Format:
Bit 7 6 5 4 3 2 1 0
Base + 0 DI7 DI6 DI5 DI4 DI3 DI2 DI1 DI0
Base + 1 DI15 DI14 DI13 DI12 DI11 DI10 DI9 DI8
Base + 2 DI23 DI22 DI21 DI20 DI19 DI18 DI17 DI16
Base + 3 DI31 DI30 DI29 DI28 DI27 DI26 DI25 DI24
** Digital Output Register Format:
Address: BASE + 0, BASE + 1, BASE + 2, BASE + 3
Attribute: write for digital output
Data Format:
Bit 7 6 5 4 3 2 1 0
Base + 0 DO7 DO6 DO5 DO4 DO3 DO2 DO1 DO0
Base + 1 DO15 DO14 DO13 DO12 DO11 DO10 DO9 DO8
Base + 2 DO23 DO22 DO21 DO20 DO19 DO18 DO17 DO16
Base + 3 DO31 DO30 DO29 DO28 DO27 DO26 DO25 DO24
♦
Digital Input Operation (Read):
The digital input states are read as a single byte from the port at
address BASE+N (N= 0,1,2,3). For each of the 8 bits within the byte
corresponding to particular digital input, a high bit (1) signifies the
input is energized, a low bit (0) signifies the input is de-energized.
For example:
In BASIC,
05 BASE=&H2A0
10 VALUE1 = INP(BASE + 0) ‘Read DO0 - DI 7
20 VALUE2 = INP(BASE + 2) ‘Read DO16 - DI 23