ex16 - counter.bs2

proteus得一些经典例子

' {$STAMP BS2}
' ==============================================================================
'
' File...... Ex16 - Counter.BS2
' Purpose... Counts external events
' Author.... Parallax
' E-mail.... [e-mail]
' Started...
' Updated... 01 MAY 2002
'
'
' ==============================================================================
' ------------------------------------------------------------------------------
' Program Description
' ------------------------------------------------------------------------------
' Counts extenal events by wait for a low-to-high transition on the event
' input pin.
' ------------------------------------------------------------------------------
' Revision History
' ------------------------------------------------------------------------------
' ------------------------------------------------------------------------------
' I/O Definitions
' ------------------------------------------------------------------------------
EventIn VAR In15 ' event input pin
' ------------------------------------------------------------------------------
' Constants
' ------------------------------------------------------------------------------
IsLow CON 0
IsHigh CON 1
Target CON 1000 ' target count
' ------------------------------------------------------------------------------
' Variables
' ------------------------------------------------------------------------------
eCount VAR Word ' event count
' ------------------------------------------------------------------------------
' Initialization
' ------------------------------------------------------------------------------
Init:
PAUSE 250 ' let DEBUG window open
DEBUG CLS, "Started... ", CR
eCount = 0 ' clear counter
' ------------------------------------------------------------------------------
' Program Code
' ------------------------------------------------------------------------------
Main:
GOSUB Wait_For_Count ' wait for 1000 pulses
DEBUG "Count complete."
END
' ------------------------------------------------------------------------------
' Subroutines
' ------------------------------------------------------------------------------
Wait_For_Count:
IF (EventIn = IsLow) THEN Wait_For_Count ' wait for input to go high
eCount = eCount + 1 ' increment event count
DEBUG Home, 10, "Count = ", DEC eCount, CR
IF (eCount = Target) THEN Wait_Done ' check against target
Wait_Low:
IF (EventIn = IsHigh) THEN Wait_Low ' wait for input to go low
GOTO Wait_For_Count
Wait_Done:
RETURN