Pin Variables

A Pin type variable is unique to the Positron compilers and allows a Port.Pin’s mask to be transferred, instead of the contents of the Port.Pin to be read or written.

Example 1.

' Create an SPI interface procedure to talk to several separate devices
'
  Device = 24FJ64GA002      ' Select the device to compile for
  Declare Xtal = 16   ' Tell the compiler the device will be operating at 16MHz
'
' Create the clock and data and CS lines as Pin variables
'
  Dim MyDataPin as Pin      ' Holds the pin to use for the SPI data line
  Dim MyClockPin as Pin      ' Holds the pin to use for the SPI clock line
  Dim MyCSPin as Pin        ' Holds the pin to use for the SPI CS line
'
' Talk to a device using an SPI interface
'
Proc SPI_Send(pData as Pin, pClock as Pin, pCS as Pin, pValue as Byte)
  PinLow pCS
  Shout pData, pClock, MsbFirst_L, [pValue]
  PinHigh pCS
EndProc
'
' Set the clock and data and CS lines
'
  MyDataPin = PORTB.3
  MyClockPin = PORTB.4
  MyCSPin = PORTB.5
  SPI_Send(MyDataPin, MyClockPin, MyCSPin, 127)
'
' Or send the clock and data and CS lines as Port.Pin
'
  SPI_Send(PORTB.0, PORTB.1, PORTB.2, 127)

Example 2.

' Flash an LED on each pin of PORTB
'
  Device = 24FJ64GA002      ' Select the device to compile for
  Declare Xtal = 16   ' Tell the compiler the device will be operating at 16MHz

  Dim MyPin as Pin           ' Holds the pin to use for the flashing LED on the port

  Do
     For MyPin = PORTB.0 To PORTB.7
       PinHigh MyPin
       DelayMs 500
       PinLow MyPin
       DelayMs 500
     Next
  Loop

See also : Aliases, Arrays, Dim, Symbol, FloatIng Point Math.

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