Advantech PCM-3753I, User Manual

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PCM-3753I User Manual 22
3.3.7 Pattern Match Interrupt Function
The PCM-3753I provides the pattern match interrupt function for port
A0. It monitors the status of the enabled input channels, which are cho-
sen in Base+24 (or Base+56 for the PCM-3753IE), and compares the
received state values with the pre-set state values written in Base+20
(Base+52 for the PCM-3753IE). When the actual state values match the
pre-set state values, the PCM-3753I will deliver an interrupt signal to the
system. This function releases the CPU from the burden of polling all of
the I/O points, enabling a PC to handle more I/O points with higher
performance. The following is an example.
Example 3.1 Assume that the pattern match function for the I/O
channels PA01, PA02, PA06 and PA07 of the PCM-3753I is enabled (i.e.
PA00, PA03, PA04 and PA05 on the PCM-3753I and port A0 on the
PCM-3753IE are ignored during the pattern match monitoring process).
The user can set the pattern match values for the enabled input channels,
and these will be compared to the actual channel states of the enabled
channels. The following is an example.
a) First, enable the pattern match interrupt function for channels PA01,
PA02, PA06 and PA07
b) Write the pre-set pattern-match state of the enabled channels
c) Finally, enable the pattern match function for port A0 of the PCM-
3753I by writing a “1” in bit 0 of Base+16.
Bit #
7 6 5 4 3 2 1 0
Base+24
1 1 0 0 0 1 1 0
Bit #
7 6 5 4 3 2 1 0
Base+20
1 0 X X X 1 1 X
M2 Description
1 Enable the change of state interrupt function for port A0
0 Disable the change of state interrupt function for port A0