A C R O S S E R
T E C H N O L O G Y
12
9. Connect all cables and cords you previously removed in step
3.
CHAPTER 3 REGISTERS AND PROGRAMMIMG
3.1 OUTPUT REGISTERS
The AR-B2104 occupies 4 consecutive addresses in the PC I/O
address space of which only three addresses are actually used.
The base or starting address is selected during the installation
procedure. The three registers of the AR-B2104 are located as
follows:
ADDRESS
OUTPUT REGISTER
INPUT STAT
BASE+0
Port 1 (write)
Port 1 (rea
BASE+1
Port 2 (write)
Port 2 (rea
BASE+2
Port 3 (write)
Port 3 (rea
BASE+3
Not used
Not used
Note that all ports are 8 bits (one byte) wide and require byte
oriented write operations rather than word operations. AII out-
puts in a port are updated simultaneously. Writing a low (0) to a
channel within a port deactivates (high impedance) the output.
Writing a high (1) to a channel activates (reach to common