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Clearing Data from
Synchronous Input
and Output Ports
Synchronous
Control and Status
Pins
Digital Module Operation 7-16
Data may be cleared from all synchronous input and output ports
with
the
DIGITAL:SYNCHRONOUS:CLEAR
command does the following:
A) Clears any data loaded into a synchronous output port.
B) Clears any data read into a synchronous input port.
C) Sets the Index for the output and input ports to 0.
Examples of the command are shown below.
Clears module 7 synchronous input and output ports:
DIG:SYNC:CLEAR (@7)
Clears modules 7, 11, and the module assigned the name "DIGIO".
DIG:SYNC:CLEAR (@7,DIGIO,11)
The CLKIN input pin of the 1260-114 is used to clock synchronous
data into and out of the module. Each time a clock edge is
presented to this input, the module generates an interrupt to the
1256.
The 1256 responds to this interrupt by writing the next data byte
from each synchronous output port, and reading a new data byte
from each synchronous input port.
The BUSY status line on the 1260-114 module is asserted until the
1256 is ready to accept a new CLKIN line. Any new CLKIN pulses
received while the BUSY line is asserted will be ignored.
The CLKIN signal is edge sensitive. The active edge is positive at
power-up and after a *RST command. This may be set to the
negative (falling) edge by using the command:
DIG:SYNC:CLOCK INVERTED
command. It may be set back to the positive (rising) edge by using
the command:
DIG:SYNC:CLOCK NORMAL
The BUSY signal is active high after power-on and after a *RST
command. This may be set to be active low by sending the
command:
DIG:SYNC:BUSY INVERTED
1256E User Manual
command.
Racal Instruments © 2002
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