**ShowPlay Reference Manual, Chapter 3 (ControlVariables): dstartmask**

===== Dstartmask -- Digital Trigger Signal =====
The DSTARTMASK variable is used to specify which bits of a digital signal will be used to trigger the start of a paradigm. 

DSTARTMASK is used in conjunction with [[jvs:cigal:showplay:manual:chapter3:trigtype|TRIG_FLAG]] and[[jvs:cigal:showplay:manual:chapter3:trigtype|TRIGTYPE]], which indicate which external signal is to be used for the trigger. If [[jvs:cigal:showplay:manual:chapter3:trig_flag|TRIG_FLAG]] is non-zero, the meaning of DSTARTMASK is controlled by the value of [[jvs:cigal:showplay:manual:chapter3:trigtype|TRIGTYPE]] as:

  TRIGTYPE=1 - DSTARTMASK indicates which digital input bits on DIGIO would trigger
  TRIGTYPE=2 - DSTARTMASK is an 8-bit ASCII code would trigger 
               (from keyboard, mouse, or similar) (see ASCII_CODES)
  TRIGTYPE=5 - DSTARTMASK indicates which digital input bits on port ATRIG_CHAN would trigger

**See Also:**\\
[[jvs:cigal:showplay:manual:chapter3:trig_flag|Trig_flag]], 
[[jvs:cigal:showplay:manual:chapter3:trigtype|Trigtype]],
[[jvs:cigal:showplay:manual:chapter3:atrig_chan|Atrig_chan]],
[[jvs:cigal:showplay:manual:chapter3:atrig_val|Atrig_val]],
[[jvs:cigal:manual:chapter4:digio|Digio]],
[[jvs:cigal:manual:chapter1:ascii_codes|ASCII_codes]]\\
[[jvs:cigal|CIGAL Home]], 
[[jvs:cigal:manual|CIGAL Manual]], 
[[jvs:cigal:showplay|ShowPlay Home]], 
[[jvs:cigal:showplay:manual|ShowPlay Manual]], 
[[jvs:cigal:showplay:manual:chapter3|InputParameters List]], 
[[jvs:cigal:showplay:manual:help|Manual Help]]