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Project:Hello Palm in Framed mode via IrTx
Source Code:PIC Assembler
PIC:16F628
Interface:IrTx
Authors:Waldemar Neto & Ravi Deo
Last Updated:7th April 2005

Project Description

This sample PIC project is based upon the typical "Hello World" program. The PIC transmits the string "Hello Palm" repeatedly via Infra-red (using raw SIR mode). It demonstrates the use of framed data infra-red transmission and reception capability, end to end (PIC to IrTx to Palm). This project is most useful for PDAs which do not support raw SIR mode, but do support framed mode (such as Palm Zire 21). Check the PDA compatability page for further information.

Project Download

Hello Palm in Framed mode via IrTx : Zip file containing Source ASM and Binary HEX files for 16F628 (approx 3KB).

Hardware Schematic

The following schematics show the circuit setup for using the PIC16F628. The Infra-red bit-stream output from the PIC (pin 8) feeds the Infra-red transmitter unit (IrTx). It is possible to use a 4MHz 3-pin ceramic resonator as the clock source (less the capacitors and middle pin to ground).

16f628

Source Code

The sample source code assumes use of an external 4MHz crystal oscillator or (external clock XT mode) on the PIC16F628 / PIC16F84.

The source code comprises of the following subroutines: 
TxChIr:      Standard SirPic subroutine to transmit char via Infra-Red
IrPulse0:    transmits a '0' bit pulse
IrPulse1:    transmits a '1' bit pulse
SpWaitDelay: Standard SirPic delay routine
Note that each variable length data packet is framed with a starter and trailer byte. The start of frame byte is hex:C0, and the trailer byte is hex:C1. The encapsulated data packet should not contain either of these characters.

SirPic Settings

SirPic Communication and Options settings should be configured as shown below (Note: Port=Framed).

16f628   16f628

SirPic Output

On starting the SirPic log session, you should see the following data being captured.

16f628

For PDA users which have raw SIR support, try switching back to raw SIR mode, and you can see the unfiltered framing characters (0xC0 and 0xC1).