Flow control

Flow control

Flow control is used in serial devices to allow them to better communicate when they are ready to send/receive data. For most devices it should be switched off, unless we know for sure that the device needs to use it. We have seen a number of cases in the past where having it on when not necessary has caused issues.

Flow control comes in two varieties, hardware and software.

Hardware flow control

Set using

$(IFNOTDEVSIM) $(IFNOTRECSIM) asynSetOption("$(ASERIAL)",0,"crtscts","Y")

in the device's st.cmd. To turn this off set it to N or remove the line completely. Under windows there is a further option to set it to D which ensures the hardware lines are floating (this is usually unnecessary).

Software flow control

Set using

$(IFNOTDEVSIM) $(IFNOTRECSIM) asynSetOption("$(ASERIAL)",0,"ixon","Y") 
$(IFNOTDEVSIM) $(IFNOTRECSIM) asynSetOption("$(ASERIAL)",0,"ixoff","Y") 

in the device's st.cmd. To turn this off set it to N or remove the line completely.