Choice of Communication Protocols btwn PIC and Palm Pilot?

MikeValencia · Joined: 04 Aug 2004 Posts: 238 Location: Chicago

I did a search in the archives and saw that RS232 is one way that a PIC would communicate with a handheld (e.g. iPAQ, Palm, etc.)

Is RS232 my only choice? I don't have a handheld, but I figure there are other choices out there that some PICs support. How about USB? Can a Palm be the USB host, and a PIC be the usb slave?

Anything else? Such as CAN? There are no CAN interfaces on handhelds, right?

Now i2c and SPI would be out of the question i think.

rwyoung · Joined: 12 Nov 2003 Posts: 563 Location: Lawrence, KS USA

iRDA. Maxim-IC makes (made?) a couple of different iRDA to serial chips that make the job pretty easy.
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Rob Young
The Screw-Up Fairy may just visit you but he has crashed on my couch for the last month!

rwyoung · Joined: 12 Nov 2003 Posts: 563 Location: Lawrence, KS USA

iRDA. Maxim-IC makes (made?) a couple of different iRDA to serial chips that make the job pretty easy. However the one time I did this was several years ago with an early model Palm III. Since then I think the protocol has changed. I haven't kept up on the subject.

Another choice would be BlueTooth. There are lots of choices for BlueTooth from 100% build-it-yourself to complete modules.

Zigbee might be on the horizion for newer PDA/Palm devices.

USB 2Go is available on some PDA/Palms (not exactly the same as USB). Again lots of choices on USB chips, assuming a USB2Go device can host a standard USB perpherial. FTDI, Cypress Semi, Philips, Microchip are four companies that have perpherial solutions. If you need USB2Go on both sides (again, I haven't kept up) then the field narrows a bit but Cypress Semi and Philips are a starting point when looking for chip sets.
_________________
Rob Young
The Screw-Up Fairy may just visit you but he has crashed on my couch for the last month!

Douglas Kennedy · Joined: 07 Sep 2003 Posts: 755 Location: Florida

The irda has very limited range ( just a few feet). The only pleasant way is via the rs232.

Personal experience

Palm is very paranoid about information concerning the Palm PDAs.
I once tried and failed with a TCP/IP over ethernet interface via a Palm ethernet cradle that at one time was $250 but sells for under $5 on E-bay. The price reduction in part is because Palm is so secretive about the workings of even obsolete parts. Palm uses rs232 and goes through an encrypted handshake before binding to the ethernet enabled cradle. Once connected the packets are unencrypted so go figure. It is probably to do with Palm's quirky hotsync concept in which PDA's are software married to a PC host partner and authenticated only at setup time. A request for a circuit diagram of the cradle invoked Palm paranoia.
I was a Palm developer at that time but they still had their secretive view of things. If anyone jumped through the Palm hurdles I'd love to hear from them.
As for Palm I believe they would have 10 times the sales if they could be open about the PDA internals and get over the fear that everyone is out to steal their business from them .

Guest · Posted: Tue Jan 18, 2005 2:46 pm