Practical Sub Routine Example

[William Roth]

Here is what I think is a good and useful example of a sub routine. When called, this sub will blink an LED for the number of times and duration as determined by the input parameters.

This is intended to demonstrate how to create and use a SUB with a useful example.

The syntax is:

Flash_LED (numtimes, OnTime, (optional) OffTime)

Where numtimes is from 1 - 255 and OnTime/OffTime is from 0 - 65535 ms. If OffTime is not entered, then OffTime = OnTime.

Below is the actual sub routine:

Sub Flash_LED (in numtimes, in OnTime as WORD, Optional OffTime as WORD = OnTime)
repeat numtimes
    set LED on
    wait OnTime ms
    set LED OFF
    wait OffTime ms 
end repeat
End Sub

Below is a working example program using a PIC 18F25K22. Change Settings/PORTS as needed for other Chips. Connect an LED to the LED pin through a 1K series resistor:

#chip 18F25K22, 16
#config OSC = INTIO67, MCLRE = OFF, XINST = OFF

#define LED PORTC.1       'Led on PIN 14 via 1K resistor
DIR LED OUT

wait 1 sec

;======== MAIN PROGRAM LOOP ================
Do
   Flash_LED 3,250        '3 Flashes 250 ms equal on/off time
   Wait 2 Sec
   Flash_LED 5,250,500    '5 flashes On 250 ms / off 500 ms
   Wait 2 Sec
   Flash_LED 10,100       '10 rapid flashes
   Wait 2 Sec
Loop
;==========================================

Sub Flash_LED (in numtimes, in OnTime as WORD, optional OffTime as word = OnTime)

    repeat numtimes
        set LED on
        wait OnTime ms
        set LED OFF
        wait OffTime ms
    end repeat
 End Sub

Enjoy

[viscomjim]

GREAT EXAMPLE thanks!!!

[Anobium]

Agree. I have moved to the Help File. We always need good example code.