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MikeValencia
Joined: 04 Aug 2004 Posts: 238 Location: Chicago
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Choice of Communication Protocols btwn PIC and Palm Pilot? |
Posted: Tue Jan 18, 2005 7:03 am |
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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. |
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rwyoung
Joined: 12 Nov 2003 Posts: 563 Location: Lawrence, KS USA
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Posted: Tue Jan 18, 2005 8:50 am |
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iRDA. Maxim-IC makes (made?) a couple of different iRDA to serial chips that make the job pretty easy. _________________ Rob Young
The Screw-Up Fairy may just visit you but he has crashed on my couch for the last month! |
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rwyoung
Joined: 12 Nov 2003 Posts: 563 Location: Lawrence, KS USA
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Posted: Tue Jan 18, 2005 8:55 am |
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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! |
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Douglas Kennedy
Joined: 07 Sep 2003 Posts: 755 Location: Florida
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Posted: Tue Jan 18, 2005 1:43 pm |
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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 . |
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Guest
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Re: Choice of Communication Protocols btwn PIC and Palm Pilo |
Posted: Tue Jan 18, 2005 2:46 pm |
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MikeValencia wrote: | 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. |
OK it appears you are in the market for a handheld device, so it may not be a Palm that you will end up with, in which case I would recommend something that runs Microsoft Windows CE.NET also known as Pocket PC2003 like the iPAQ or Dell hand helds. Palm is a dying brand.
Most current iPAQ's come with Bluetooth class 1 device which will get you a practical range of 60 to 300 feet depending on how clear the line of sight is.
Bluetooth will free your design from cables, and give you the same RS-232 type of interface for the programs on each end of the link.
I've been using BlueRadios modules and they are very small and easy to use., not cheap.
Most iPAQ's also come with irda and if your design is not going outdoors then expect about 6-10 feet of range (indoors) However there is the added problem of how to communicate with multiple devices, with Bluetooth that's not a problem. Also the infrared device must point at each other.
Hans W |
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