Hi Russ,
I'll add some comments to your questions below.
>1. The serial port on the instrument is a 3-wire connection (RD, TD,
>GND). The instrument implements a XON/XOFF data flow control mechanism.
>I noticed in the Palm serial port information that RTS and CTS hardware
>handshaking are required for baud rates exceeding 2400 bps. This
>apparently results from the small 8-byte buffer on the UART. Is there no
>provision in the Palm OS Serial Manager for XON/XOFF flow control? Is
>there any other way to increase the data rate without using the hardware
>handshake?
>
>
>2. For this application, my client would like to have the instrument
>connected to the Palm serial port directly without using the cradle. I'm
>assuming that if we participate in the "Serial Port & Modem Casing
>Program" we will receive information concerning vendors who will sell us
>(custom) cables for the Palm.(?)
The cables are actually quite easy to make. You can now get 9 pin serial
connectors which have telephone-link jacks on each end (RJ-45 I think is
what they're called), so if you can find someone to make the cables
for you, this might be a good route to take.
>Is it possible to power the Palm over a dedicated
>serial cable using pin 2(+3.3V) and pin 10 (SG) of the serial
>connection? Do you know if this has ever been done before?
Yes, we do this for an application that we've developed. We run a 3.3V
signal on unused serial wire. We then connect a diode between the
pad in the Palm and the battery terminal. Presto, everything works.
Great for testing, too, as I don't need a crate-load of batteries! :)
The big problem: it voids the Palm warranty because we're soldering
new stuff onto the "gold" serial contacts. See below for more
comments.
>
>4. I'm assuming there is no non-volatile memory in the device without AA
>batteries. If the Palm is powered over a dedicated serial cable, could
>AA batteries still be used to produce 'non-volatile' memory between
>power cycles of the instrument?
There is a small amount of time between when the batteries/power is
disconnected and the device going dead. There is a nice capacitor
in the device that will keep things going for a bit. We get around
this by installing two lithium-ion rechargeable batteries in the
device. When power is present, it will run the device and charge
the batteries, but when the power is disconnected the device will run
off the batteries for awhile.
You may want to check out http://www.revolvedesign.com. We helped
them design a "vehicle mount" device for holding Palm devices. They've
since extended it with a rechargeable battery pack. The dedicated power
source is connected directly to the battery pack, and this pack is then
connected to the Palm battery leads. This avoids having to make h/w
mods to the Palm device. We will be switching our stuff to this setup
soon, as well. Now we won't keep voiding the warranties! :)
>5. Also for the Palm powered over a dedicated cable, can the 'sleep'
>mode be disabled using the Palm OS? If not, can the device 'wake up'
>when a character is received on the serial port?
Yup, there is a command that you can use to turn off the "sleep mode".
We use it, but I can't remember it off hand. Don't know about the
serial question, though.
>6. Is it possible to write an application using the Palm OS such that on
>power up the application starts automatically?
Yes, check out Hack Master and Logo Hack. With these two you can setup
the Palm device so that it displays a "splash screen" when it starts
up and then starts another app. We do this to start our app, but
I don't know the exact details (I didn't write this part).
Hope this helps,
-paulo
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Paulo F. Ferreira
AirLink Communications, Inc. San Jose, California
http://www.AirLink.com
