AsynEchoDriver - ISISComputingGroup/ibex_developers_manual GitHub Wiki

Asyn provides an echo driver that will return on a read what was last provided by a write. This can be used for some very basic stream device testing / simulation e.g. if the real function is

getFrequency {
    out "FREQ?"; in "%f";
}

Then by connecting the device to the echo driver you could write

Terminator = ETX;

getFrequency {
    out "10.0"; in "%f";
}

Note, you must have a terminator otherwise the echo driver gets confused and won't work.

Potentially you could have both a real getFrequency() and a dummy getFrequencyTest() function in the protocol file and then control with one was used by writing getFrequency$(TEST=) in the DB file and setting TEST=Test with dbLoadRecords()

To enable support for the echo driver in a Makefile:

• Add asynEcho to $(APPNAME)_LIBS
• Add drvAsynEcho.dbd to $(APPNAME)_DBD

And then in st.cmd use e.g.:

echoDriverInit(“L0”, 0.1, 0, 0)

Where L0 is the asyn port name and 0.1 is, in this case, how long to take to return a reply (this must be greater than zero). The other options allow selecting noautoconnect or multi-device if required.