On Thu, 17 Aug 2000, Don Hyde wrote:

> On the Palm side, you need to go to their developer website.  PalmOS has a
> "IR Library" if I recall the name correctly, which allows you to perform
> low-level IR communications.

I'm not sure what you mean by "low-level". Using the trick Scott Newell mentions
(which is quite clever I might add), you can't get any lower. The IrDA Libray on
the Palm exposes the IrDA stack at the IrLMP and TinyTP layers. The Exchange
Manager implements a subset of IrObex.

>
> The IRDA protocol is at least as complex as TCP/IP, and would be difficult
> to fit into a PIC.   The IRObex protocol that Palm uses to exchange data is
> yet another complex protocol run on top of the basic IRDA stuff, and is even
> less attractive for PIC implementation.


I agree that the IrDA stack is extremely complicated when compared to other
protocols. But even if you manage to tackle the tricky software you still have
to deal with the hardware. For example, the IrDA specification says that the
pulse widths for SIR (Serial Infrared) can be as narrow as 1.4uS or 7
instruction cycles for a 20Mhz PIC. I'm not sure about the Pilot, but the JetEye
Ir dongles emit these narrow pulses. (BTW, it's a lot easier to develop on a PC
and using a dongle than it is on the Palm Pilot. I've been doing this with Linux
here lately.)

My recommendation is try Scott N's hack and forget about the IrDA stack ---
assuming of course that all you need to do is to talk to a Palm Pilot.

Scott

--
http://www.piclist.com hint: To leave the PICList
mailto:piclist-unsubscribe-request@mitvma.mit.edu