RE: Multiple serial ports for Pocket PC?

From: Carl Nilsson <
>
Date: Wed, 21 Apr 2004 00:45:25 +1000

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Paul:
thanks for info. I'll find out what GPIO's are, not to mention SPI and 
MAX3100's and then I'll be able to understand and comment meaningfully!

At 11:59 PM 4/20/04, you wrote:

>One inexpensive solution is to do what you suggest by using a set of PIC 
>microcontrollers, and have them network the multiple serial ports 
>together. To my knowledge there are no microcontrollers with more then 2 
>serial UARTs. So, this might be hard to do:
>
>    [pocket pc] ---> PIC ---------> device1
>                      \--> PIC ----> device2
>                            \--> PIC ---> device3
>                                  \---> PIC ---> device4
>
>There are two better alternatives. First you could get some software UART 
>code (basically use GPIOs as 3.3v serial ports, you only need 3 GPIOs to 
>emulate a true Asynchronous serial port (Rx,Tx,Gnd)). Or consider using 
>SPI to talk to a bank of Max3100s (UART<->SPI chips):
>
>    [pocket pc] ---> PIC ---(SPI)---> MAX3100 ---> device1
>                                 ---> MAX3100 ---> device2
>                                 ---> MAX3100 ---> device3
>                                 ---> MAX3100 ---> device4
>
>SPI allows multiple devices to share the same bus. You just need a GPIO 
>for each slave device to select it. The Max3100 comes in a 16 pin QSOP, or 
>14 pin DIP package, and does require a crystal. The 3100 runs $7 from Digikey.
>
>-Paul
>
>R. Paul McCarty
>Vitronics Inc
>tel: (732) 389-0244 x30
>fax: (732) 544-9431
>
>
>
>-----Original Message-----
>From: Carl Nilsson [mailto:]
>Sent: Monday, April 19, 2004 6:52 PM
>To: 
>Subject: RE: Multiple serial ports for Pocket PC?
>
>
>I haven't checked out this yet.  I presume you are telling me that TDK 
>make a Bluetooth  ... Serial Module (BISM ?) for $70.   That's getting 
>closer to the mark, but the problem there is each serial line needs one so 
>I am up for, say, 4 X $70.   Not out of the question.  I appreciate the 
>info on Bluetooth, about which I know next to nothing.  I also know that I 
>should look into it soon!   A mixed approach might be to use a PIC 
>microprocessor or two to collect all the serial lines running at 9600 baud 
>or less, put them out as one serial stream and then use a BISM or two.
>Thanks, Carl
>
>At 02:08 AM 4/20/04, you wrote:
>
>
>TDK BISM $70
>
>Check out http://www.tekgear.com/category.cfm?category=Bluetooth%20OEM for 
>more OEM modules that might do the trick as well.
>
>Remember that the Bluetooth SPP Profile will only support a certain number 
>of concurrent Serial Connections.  I believe the limit is 4 concurrent 
>connections with 7 devices that can be discovered.  This means that there 
>is a limit to how many devices you can poll at one time. If you want to 
>poll a different device that is not in your list of 4 active devices, you 
>software has to drop one of the connections and pair up with the new 
>device you want to poll.  Keep this in mind when selecting Bluetooth as an 
>alternative to wired connections.
>
>-Tony
>
>-----Original Message-----
>
>From: Carl Nilsson [mailto:]
>
>Sent: Saturday, April 17, 2004 5:44 AM
>
>To: 
>
>Subject: Re: Multiple serial ports for Pocket PC?
>
>
>G'Day Ralf:
>
>Thanks for your considered replies.  I'm using an iPAQ h 2115 at the 
>moment which does have Bluetooth.   Haven't tried it yet and I'm a bit 
>wary of possible interference from airport radar etc in an aircraft and 
>interference to other devices in the aircraft, but it is certainly worth 
>looking into.   Don't know till you try things.   Thanks for the TDK 
>suggestion  - depends on price.  I would need one of these adapters for 
>each device.
>
>Carl
>
>  At 08:19 PM 4/17/04, you wrote:
>
>
>Hello Carl,
>
>
>thinking about your application scenario again I considered another
>
>solution that might be easiest to deploy.
>
>It uses Bluetooth - either your PDA is already equipped with it - or you
>
>may use a CF BT card.
>
>
>For your serial data sources => you may use a module that does a serial
>
>cable replacement over BT. The most compact one that I'm aware of (and
>
>that I actually use sucessfully) is a module made by TDK
>
>         http://www.tdksystems.com/tdk_bluetooth/bluetooth_serial_module.asp
>
>
>Software on your PDA will let you set up multiple serial connections over
>
>Bluetooth in parallel (at least with a PDA running Linux and the Bluez BT
>
>stack). Your application on the PDA can then individually cope with the
>
>data coming from each source.
>
>
>Maybe that is an approach for you.
>
>Regards
>
>  Ralf
>
>
>---------------------------------------------------------------
>
>Dr. Ralf Ackermann            _         
>
>Multimedia Communications |/ | | |\/|           Merckstrasse 25
>
>                           |\ |_| |  |  64283 Darmstadt, Germany
>
>Tel.: (+49) 6151 16-6138                Fax: (+49) 6151 16-6152
>
>---------------------------------------------------------------
>
>              http://www.kom.tu-darmstadt.de/~rac
>
>---------------------------------------------------------------
>
>
>--
>
>Subscription/unsubscription/info requests: send e-mail with subject of
>
>"subscribe", "unsubscribe", or "info" to 
>
>Wear-Hard Mailing List Archive (searchable): http://wearables.blu.org
>
>Please, *PLEASE* don't subscribe through a forward/expander/false domain
>
>
>Carl Nilsson
>
>137 Gordons Hill Road
>
>Lindisfarne
>
>Tasmania 7015
>
>Australia
>
>Carl Nilsson
>137 Gordons Hill Road
>Lindisfarne
>Tasmania 7015
>Australia
>
>--
>Subscription/unsubscription/info requests: send e-mail with subject of
>"subscribe", "unsubscribe", or "info" to 
>Wear-Hard Mailing List Archive (searchable): http://wearables.blu.org
>Please, *PLEASE* don't subscribe through a forward/expander/false domain

Carl Nilsson
137 Gordons Hill Road
Lindisfarne
Tasmania 7015
Australia 
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<body>
<font size=3>Paul:<br>
thanks for info. I'll find out what GPIO's are, not to mention SPI and
MAX3100's and then I'll be able to understand and comment meaningfully!
<br><br>
<br>
At 11:59 PM 4/20/04, you wrote:<br><br>
<blockquote type=cite class=cite cite="">One inexpensive solution is to
do what you suggest by using a set of PIC microcontrollers, and have them
network the multiple serial ports together. To my knowledge there are no
microcontrollers with more then 2 serial UARTs. So, this might be hard to
do:<br><br>
   [pocket pc] ---> PIC ---------> device1<br>
                    
\--> PIC ----> device2<br>
                          
\--> PIC ---> device3<br>
                                
\---> PIC ---> device4<br><br>
There are two better alternatives. First you could get some software UART
code (basically use GPIOs as 3.3v serial ports, you only need 3 GPIOs to
emulate a true Asynchronous serial port (Rx,Tx,Gnd)). Or consider using
SPI to talk to a bank of Max3100s (UART<->SPI chips):<br><br>
   [pocket pc] ---> PIC ---(SPI)---> MAX3100 --->
device1<br>
                               
---> MAX3100 ---> device2<br>
                               
---> MAX3100 ---> device3<br>
                               
---> MAX3100 ---> device4<br><br>
SPI allows multiple devices to share the same bus. You just need a GPIO
for each slave device to select it. The Max3100 comes in a 16 pin QSOP,
or 14 pin DIP package, and does require a crystal. The 3100 runs $7 from
Digikey.<br><br>
-Paul<br><br>
R. Paul McCarty<br>
Vitronics Inc<br>
tel: (732) 389-0244 x30<br>
fax: (732) 544-9431<br><br>
<br><br>
-----Original Message-----<br>
From: Carl Nilsson
[<a href="mailto:" eudora="autourl">mailto:</a>]<br>
Sent: Monday, April 19, 2004 6:52 PM<br>
To: <br>
Subject: RE: Multiple serial ports for Pocket PC?<br><br>
<br>
I haven't checked out this yet.  I presume you are telling me that
TDK make a Bluetooth  ... Serial Module (BISM ?) for
$70.   That's getting closer to the mark, but the problem there
is each serial line needs one so I am up for, say, 4 X $70.  
Not out of the question.  I appreciate the info on Bluetooth, about
which I know next to nothing.  I also know that I should look into
it soon!   A mixed approach might be to use a PIC
microprocessor or two to collect all the serial lines running at 9600
baud or less, put them out as one serial stream and then use a BISM or
two.<br>
Thanks, Carl<br><br>
At 02:08 AM 4/20/04, you wrote:<br><br>
<br>
TDK BISM $70<br>
 <br>
Check out
<a href="http://www.tekgear.com/category.cfm?category=Bluetooth%20OEM" eudora="autourl">http://www.tekgear.com/category.cfm?category=Bluetooth%20OEM</a>
for more OEM modules that might do the trick as well.<br>
 <br>
Remember that the Bluetooth SPP Profile will only support a certain number of concurrent Serial Connections.  I believe the limit is 4 concurrent connections with 7 devices that can be discovered.  This means that there is a limit to how many devices you can poll at one time. If you want to poll a different device that is not in your list of 4 active devices, you software has to drop one of the connections and pair up with the new device you want to poll.  Keep this in mind when selecting Bluetooth as an alternative to wired connections.<br>
 <br>
-Tony<br><br>
-----Original Message-----<br><br>
From: Carl Nilsson [<a href="mailto:" eudora="autourl">mailto:</a>] <br><br>
Sent: Saturday, April 17, 2004 5:44 AM<br><br>
To: <br><br>
Subject: Re: Multiple serial ports for Pocket PC?<br><br>
<br>
G'Day Ralf:<br><br>
Thanks for your considered replies.  I'm using an iPAQ h 2115 at the moment which does have Bluetooth.   Haven't tried it yet and I'm a bit wary of possible interference from airport radar etc in an aircraft and interference to other devices in the aircraft, but it is certainly worth looking into.   Don't know till you try things.   Thanks for the TDK suggestion  - depends on price.  I would need one of these adapters for each device.<br><br>
Carl<br><br>
 At 08:19 PM 4/17/04, you wrote:<br><br>
<br>
Hello Carl,<br><br>
<br>
thinking about your application scenario again I considered another <br><br>
solution that might be easiest to deploy.<br><br>
It uses Bluetooth - either your PDA is already equipped with it - or you <br><br>
may use a CF BT card.<br><br>
<br>
For your serial data sources => you may use a module that does a serial <br><br>
cable replacement over BT. The most compact one that I'm aware of (and <br><br>
that I actually use sucessfully) is a module made by TDK<br><br>
        <a href="http://www.tdksystems.com/tdk_bluetooth/bluetooth_serial_module.asp" eudora="autourl">http://www.tdksystems.com/tdk_bluetooth/bluetooth_serial_module.asp</a><br><br>
<br>
Software on your PDA will let you set up multiple serial connections over <br><br>
Bluetooth in parallel (at least with a PDA running Linux and the Bluez BT <br><br>
stack). Your application on the PDA can then individually cope with the <br><br>
data coming from each source.<br><br>
<br>
Maybe that is an approach for you.<br><br>
Regards<br><br>
 Ralf<br><br>
<br>
---------------------------------------------------------------<br><br>
Dr. Ralf Ackermann            _         <br><br>
Multimedia Communications |/ | | |\/|           Merckstrasse 25<br><br>
                          |\ |_| |  |  64283 Darmstadt, Germany<br><br>
Tel.: (+49) 6151 16-6138                Fax: (+49) 6151 16-6152<br><br>
---------------------------------------------------------------<br><br>
             <a href="http://www.kom.tu-darmstadt.de/~rac" eudora="autourl">http://www.kom.tu-darmstadt.de/~rac</a><br><br>
---------------------------------------------------------------<br><br>
<br>
--<br><br>
Subscription/unsubscription/info requests: send e-mail with subject of<br><br>
"subscribe", "unsubscribe", or "info" to <br><br>
Wear-Hard Mailing List Archive (searchable): <a href="http://wearables.blu.org/" eudora="autourl">http://wearables.blu.org</a><br><br>
Please, *PLEASE* don't subscribe through a forward/expander/false domain<br><br>
<br>
Carl Nilsson<br><br>
137 Gordons Hill Road<br><br>
Lindisfarne<br><br>
Tasmania 7015<br><br>
Australia <br><br>
Carl Nilsson<br>
137 Gordons Hill Road<br>
Lindisfarne<br>
Tasmania 7015<br>
Australia <br><br>
--<br>
Subscription/unsubscription/info requests: send e-mail with subject of<br>
"subscribe", "unsubscribe", or "info" to <br>
Wear-Hard Mailing List Archive (searchable): <a href="http://wearables.blu.org/" eudora="autourl">http://wearables.blu.org</a><br>
Please, *PLEASE* don't subscribe through a forward/expander/false domain</blockquote>
<x-sigsep><p></x-sigsep>
Carl Nilsson<br>
137 Gordons Hill Road<br>
Lindisfarne<br>
Tasmania 7015<br>
Australia</font></body>
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