Chapter 1
Getting to Know Your 6527
6527 Register-Level Programmer Manual
1-2
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General Operation Registers
Initialize the PCI interface before using the general operation registers. Read the ID Register,
one of the general operation registers, to verify the PCI interface is initialized properly. For
more information on the ID Register, refer to the
section in Chapter 2,
The general operation registers also include the main input and output registers. Three 8-bit
input registers report the values on the optocouplers that make up Ports 0, 1, and 2. Three 8-bit
output registers open or close the solid-state relays (SSRs) that make up Ports 3, 4, and 5. You
can read back from the output registers to determine the last value written.
Use Clear Register, another general operation register, to reset various functions such as
digital filtering and change notification.
Using the Digital Filtering Option
Enable or disable filtering on any or all 24 input lines using digital filtering. Filtering can help
eliminate glitches on input data and reduces the number of changes you need to process if you
are using digital filtering with change notification.
Enable filtering on the chosen input lines and set a filter interval, which regulates all filters
you enable. Refer to the
Digital Filtering
section in Chapter 4,
Using the 6527
, of the
6527 User Manual
.
Using the Change Notification Option
Use change notification to generate an interrupt when any input line changes. You need
to know how to write, install, and uninstall interrupt service routines to use this option.
The change notification registers consist of two masks, one specifying the lines you want
to monitor for rising edges, and another specifying the lines you want to monitor for falling
edges. You can monitor any set of input lines for rising edges, falling edges, or both.
The change notification registers also include an interrupt enable register.
You can use digital filtering concurrently with change notification to limit the rate of
interrupts. Refer to the
Change Notification
section in Chapter 4,
Using the 6527
, of the
6527
User Manual
for more details about this option.
