Input (PinInput)

Source: Positron16 Compiler User Manual, PDF page 181

Syntax

Input Port.Pin or Pin Number

PinInput Port or Port.Pin or Pin Number

Overview

Makes the specified Port or Pin an input. The name PinInput can also be used instead of the name Input. They both work exactly the same but make the source code a little clearer to read and follow.

Parameters

Port must be the name of a Port. Port.Pin must be a Port, or Port.Pin constant declaration. Pin Number can be any variable or constant holding 0 to the amount of I/O pins on the device. A value of 0 will be PORTA.0, if present, 1 will be PORTA.1, 16 will be PORTB.0 etc…

Example 1

  Input PORTB.4
                                ' Make pin-4 of PORTB an input
  Input PORTB
                                ' Make all of PORTB an input
  Input 0
                                ' Make pin-0 of PORTA an input
   Input 16
                                ' Make pin-0 of PORTB an input
  PinInput PORTB.0
                                ' Make pin-0 of PORTB an input

Example 2

' Flash each of the pins on PORTB
'
   Device = 24FJ64GA002
                                ' Select the device to compile for
   Declare Xtal = 16
   Dim PinNumber as Byte
   High PORTB
   For PinNumber = 16 to 31   ' Create a loop for the pin to flash
     Output PinNumber
                                ' Set the pin as an output
     DelayMs 500
                                ' Delay so that it can be seen
     Input PinNumber
                                ' Set the pin as an input
     DelayMs 500
                                ' Delay so that it can be seen
   Next

Notes.

An Alternative method for making a particular pin an input is by directly modifying the TRIS register: -

TRISB.0 = 1
                 ' Make bit-0 of PORTB an input

All of the pins on a port may be set to inputs by setting the whole TRIS register at once: -

TRISB = %1111111111111111 ' Set all of PORTB to inputs

In the above examples, setting a TRIS bit to 1 makes the pin an input, and conversely, setting the bit to 0 makes the pin an output. Each pin number has a designated name. These are Pin_A0, Pin_A1, Pin_A2, Pin_B0…Pin_B15, Pin_C0…Pin_C15, Pin_D0…Pin_D15 to Pin_L15 etc… Each of the names has a relevant value, for example, Pin_A0 has the value 0, Pin_B0 has the value 16, up to Pin_J15, which has the value 143.

These can be used to pass a relevant pin number to a Procedure. For example:

'
' Flash an LED attached to PORTB.0 via a procedure
' Then flash an LED attached to PORTB.1 via the same procedure
'
  Device = 24HJ128GP502
                                   ' Select the device to compile for
  Declare Xtal = 16
  Do
                                   ' Create a loop
     FlashPin(Pin_B0)
                                   ' Call the procedure to flash PORTB.0
     FlashPin(Pin_B1)
                                   ' Call the procedure to flash PORTB.1
  Loop
                                   ' Do it forever
'
' Set a pin high then an input for 500ms using a value as the pin to adjust
'
Proc FlashPin(pPinNumber As Byte)
  PinHigh pPinNumber
                                   ' Set the pin output high
  DelayMs 500
                                   ' Wait for 500 milliseconds
  PinInput pPinNumber
                                   ' Make the pin an input
  DelayMs 500
                                   ' Wait for 500 milliseconds
EndProc

Note

The name “PinInput” can also be used to replace the command Input, and this, sometimes, makes the BASIC code a little clearer to read. PinInput and Input perform exactly the same task.