Wireless Null Modem Infrared Palm Pilot Communication Device

Team Members Team Leader : –Peter Trenkle Group Members : –Huiyang Sim –Shaun McFarland –Stephen Porter

Abstract Design an infrared console that eliminates the need for a DB-9 serial cable to transmit data to a PDA Develop software that will allow users to establish a data link between the console and the Palm Pilot

Motivation Palm Pilots are cheaper and easier to carry than laptops with null modem cables Infrared technology has allowed for low- speed data links in handheld computing devices Ability to supply a cheap, convenient alternative to a laptop interfacing to an ASCII display menu

Why Use Infrared Technology? Infrared technology is perfect to replace the cable required by the RS-232 interface Low level infrared data links can transmit data at up to kbps Infrared data links are feasible at distances of up to three meters Infrared standard will allow for thousands of products to interface to our design

Design Constraints Design an Infrared Console to Establish a Data Link and Tx/Rx RS-232 data through the Infrared Data Link Transmit and Receive Infrared Data at a Rate of 19.2kbps with a Bit Error Rate of 10E-9 Develop Software for PALM to Detect a Data Link and Display ASCII Menus

Design Constraints Create a 1 meter Infrared Data Link Physical Packaging –The size will be no larger than 2” x 1.5” x 2.25” (H x W x D) –Components have small footprints Cost –The cost of parts and packaging will be < $30

Low Power Requirement Typical use of our product will be defined as 15 minute intervals, with long delays between use One 9 Volt battery will be used to supply power to our project Due to the excessive power needed by the IR transceiver, several aspects of the transmitted data are observed –screen refresh rates –amount of characters on each screen By knowing the current rating of the 9V battery 9V) we can define a simple formula showing battery life depending on current drawn

Low Power (cont.) Battery life in hours = 120mAh / X (# mA drawn) The PIC, External UART, and Line Driver pull approximately 2mA at the given clock speed (4Mhz) The IR Transceiver draws several times more power (~100mA) depending on the length of time it transmits This will be limited by controlling the duty cycle and transmission rate of the IR Transceiver Maximum Power will be determined when final prototype is developed

Development Plan Hardware Design Finished Schematic Palm OS Dev. “Hello World” On Palm PIC C Firmware Dev. Determination of Components Basic Serial I/O into the PIC Packetize DataSerial Com Via Palm Implement IrComm StandardInfrared Com Via Palm Final Testing and System Integration

Hardware Design Hardware was chosen by considering the Design Constraints –Power Consumption –Performance at low clock speeds, further decrease power consumption –IrDA Timing Compatibility –Large amounts of buffer space for creating packets of data

Diagram of Hardware MAX3100 Infrared Transceiver To PALM From PALM From 19.2 kbps RS-232 Line Driver PIC 16F877 On-Board UART On-Board SPI Port Maxim 3100 Controls IrDA Timing for the PIC PIC Controls capture of serial data from SPI Port and UART. This data is then decoded from/encoded into IrDA compatible data

Component Costs

Embedded Software Design –Use the PC’s serial port to transmit serial data to verify the UART –Create Modular I/O routines for SPI module on PIC –Interface the PIC to the Max3100 UART to control IrDA timing –Transmit and Receive Data between the RS-232 Interface and the Infrared Interface –Port existing IrComm Assembly Code into C Code –Build the IrDA protocol layer by layer, testing each as it is completed –Test the final software program using IrPing()

Palm OS Development Learn the basics of the CodeWarrior language for Palm OS –Work on “Hello World” program –Start with Initial Serial Port programs Create a program that allows for bi-directional serial communication –Send Data Bi-directionally from PC to Palm Pilot –Add User Input Functionality Move serial port program to interface to the Palm’s onboard infrared port

Test Specification IrPing() – IrDA protocol stack analyzer for the Palm –Will test the IR data sent by the Console and Palm –Will verify the IrDA protocol layers implemented in Firmware Oscilloscope –Will check the clocking of the SPI Port of the PIC and the Data Rate of the RS-232 Interface –Will allow complete verification of hardware design Performance Testing –Create a real world simulation environment –Perform Peak Performance Testing and Typical Use Testing PC’s IR port will act as Bit Error Rate Tester

Test Specification Design Constraint IrPING( )Performance TestingOscilloscopePC IR Port for Bit Error Rate Test Encode/Decode 19.2kbps Implement IrComm Standard Create 1 meter Data Link Hardware Palm Pilot Terminal Program Accuracy of Infrared Data Power

End of Semester Delivery Demonstrate our bi-directional Palm Pilot terminal program Any IR Links unable to be implemented will be simulated by a null modem cable Transmit/Receive IR Data with limited IrDA functionality Complete IrDA functionality will be completed by February of 2002 PC Board will be laid out and ready for order

Summary Design and Implement a small, low-power RS-232 IR console Create a Palm Pilot Program that displays ASCII data on screen Create a convenient, low-cost alternative to laptop-to-serial-cable communications

Future Applications Remote control of Serial Devices Make software compatible with different PDAs for greater market penetration TCP/IP functionality to allow for low speed internet connections on the PDA

Acknowledgements We would like to thank Dr. Robert Reese, our advisor, for all his valuable input We would also like to acknowledge Dr. Joseph Picone for his support

References [1] "About IrDA Software Protocol,” p, Infrared Data Association, Walnut Creek, California, [2] P. Barker and A. C. Boucouvalas, “Effect of Random Alignment Sway on the Performance of IrDA Handheld Devices,” p, Infrared Data Association, Walnut Creek, California, [3] M. Cremer, “An Introduction to the IrDA Protocols,” PDA Developers 2. 6, pp , Nov/Dec, [4] T. Engdahl, "Get Power Out of PC RS-232 port,” l, Epanorama.net: Electronic Circuit Desig n, August 25, [5] L. Goldberg, “Infrared Data Transmission: The Missing Link?” Electronic Desig n, pp , April 17, 1995.

References [6] "‘IrCOMM’: Serial and Parallel Port Emulation over IR (Wire Replacement),” p, Infrared Data Association, Walnut Creek, California, [7] "IrDA Data Link Design Guide," r, Hewlett Packard, Palo Alto, California, [8] C. Knutson, “Infrared Data Communications with IrDA,” presented at IrDA Conference, [9] P. Langley, “Leading Alternative for Serial Ports: IRDA,” Electronic Engineering Time s, p. 54, August 17, [10] P. Megowan, “IrDA Infrared Communications: An Overview,” p, Infrared Data Association, Walnut Creek, California, [11] T. Salazar, “UART test mode provides clock for RS-232-to-IrDA translator,” Electronic Desig n, pp , February 21, [12] "Serial Infrared Link Access Protocol (IrLAP) Version 1.1,” p, Infrared Data Association, Walnut Creek, California, 1996.