Interfacing PDA to USB

[Theo van der Merwe]

How do I interface common USB devices to a PDA? As I have recently
bought the entry level Palm Zire, I would at present be more
interested in the Palm PDA.

More specifically, I have the following questions:

1) How does the interfacing to a regular USB keyboard work? I would
like to use a full size USB keyboard with the Palm Zire. It is not
necessary to develop a driver for the PDA, a simple application in
which one can type text (which can then be copied later to e.g.
memopad) is sufficient for my purposes.

2) How does the interfacing to a USB memory stick work? I have a 128MB
Kingston data traveller which I would like to interface to the Palm
Zire. Again it is not necessary to develop a full driver to the Palm
Zire (although it would obviously be very convenient!). Rather, an
application which can store (and restore) the complete memory contents
of the Palm Zire on memory stick is required.
So I don't necessarily need to interpret the file structure of the USB
memory stick (again that would be useful, for example what file
structure is used on a memory stick?) - just a simple memory dump from
the Palm (currently limited to 2MB I think) to the USB memory stick is
required at present.

In summary I want to know how USB interfacing works in detail so I can
interface some common USB devices to a PDA (I am assuming that USB
drivers for the Palm to common USB devices is not available?). I don't
need to develop an USB driver at this stage (which might be very
difficult?). Would it be possible to interface more than one USB
device to a PDA? If so, what changes in programming is required?

Best regards,
Theo van der Merwe (ntvdmREMOVE@iafrica.com)

 

[the Wiz]

ntvdml@iafrica.com (Theo van der Merwe) wrote:

How do I interface common USB devices to a PDA? As I have recently
bought the entry level Palm Zire, I would at present be more
interested in the Palm PDA.

[snip]

In summary I want to know how USB interfacing works in detail so I can
interface some common USB devices to a PDA (I am assuming that USB
drivers for the Palm to common USB devices is not available?). I don't
need to develop an USB driver at this stage (which might be very
difficult?). Would it be possible to interface more than one USB
device to a PDA? If so, what changes in programming is required?

Best regards,
Theo van der Merwe (ntvdmREMOVE@iafrica.com)

USB is not a simple protocol like RS232, where the standard interface is
bi-directional.

The Palm is a USB slave device and cannot connect to other USB slave devices
(keyboard, etc).

What you want to do cannot be done with current devices.

This question is frequently asked in the Palm newsgroups and the answer is
always the same...

More about me: http://www.jecarter.com/
VB3/VB6/C/PowerBasic source code: http://www.jecarter.com/programs.html
Freeware for the Palm with NS Basic source code: http://nsb.jecarter.com
Drivers for Pablo graphics tablet and JamCam cameras: http://home.earthlink.net/~mwbt/
johnecarter at@at mindspring dot.dot com. Fix the obvious to reply by email.

 

[Ian Stirling]

In sci.electronics.design Theo van der Merwe <ntvdml@iafrica.com> wrote:

How do I interface common USB devices to a PDA? As I have recently
bought the entry level Palm Zire, I would at present be more
interested in the Palm PDA.

More specifically, I have the following questions:

1) How does the interfacing to a regular USB keyboard work? I would
like to use a full size USB keyboard with the Palm Zire. It is not
necessary to develop a driver for the PDA, a simple application in
which one can type text (which can then be copied later to e.g.
memopad) is sufficient for my purposes.
snip
In summary I want to know how USB interfacing works in detail so I can
interface some common USB devices to a PDA (I am assuming that USB
drivers for the Palm to common USB devices is not available?). I don't
need to develop an USB driver at this stage (which might be very
difficult?). Would it be possible to interface more than one USB
device to a PDA? If so, what changes in programming is required?

It's hardware, not software.
The PDA would have to integrate a USB host, not just a USB device.
I don't think any do.

 

[the Wiz]

Bob Stephens <stephensyomamadigital@earthlink.net> wrote:

On Thu, 18 Mar 2004 20:05:47 GMT, the Wiz wrote:

ntvdml@iafrica.com (Theo van der Merwe) wrote:

How do I interface common USB devices to a PDA? As I have recently
bought the entry level Palm Zire, I would at present be more
interested in the Palm PDA.

[snip]

Don't know if your Palm has compact flash slots, but I know of two
companies who make CF USB host adapters for PDA's.
RATOC has the CFU1U and Twin Paradox has the SolarExpress PDA.
They are intended to interface to standard HID and bulk storage devices.

good luck,


Bob

PDA is, unfortunately, a generic term.

The only PDAs with CF slots are Windows CE devices. Most Palm devices have
SD/MMC slots.

The Ratoc page specifies the devices the USB card works with:

ˇ Compaq iPAQ with CF Jacket, PC Card Jacket.
ˇ Dell Axim
ˇ Fujitsu Pocket Loox

Nothing for the Palm :-(

More about me: http://www.jecarter.com/
VB3/VB6/C/PowerBasic source code: http://www.jecarter.com/programs.html
Freeware for the Palm with NS Basic source code: http://nsb.jecarter.com
Drivers for Pablo graphics tablet and JamCam cameras: http://home.earthlink.net/~mwbt/
johnecarter at@at mindspring dot.dot com. Fix the obvious to reply by email.

 

[Theo van der Merwe]

the Wiz <look@message.body> wrote in message news:<srvj50ljrvdu9nsiei6jk3l1qv1cdfbqmk@4ax.com>...

ntvdml@iafrica.com (Theo van der Merwe) wrote:

How do I interface common USB devices to a PDA? As I have recently
bought the entry level Palm Zire, I would at present be more
interested in the Palm PDA.

[snip]

In summary I want to know how USB interfacing works in detail so I can
interface some common USB devices to a PDA (I am assuming that USB
drivers for the Palm to common USB devices is not available?). I don't
need to develop an USB driver at this stage (which might be very
difficult?). Would it be possible to interface more than one USB
device to a PDA? If so, what changes in programming is required?

Best regards,
Theo van der Merwe (ntvdmREMOVE@iafrica.com)

USB is not a simple protocol like RS232, where the standard interface is
bi-directional.

The Palm is a USB slave device and cannot connect to other USB slave devices
(keyboard, etc).

I am not sure I follow this - how does the Palm keyboard interface to

the Palm then? However, if I give you the benefit of doubt I can
rephrase the question and ask how does interfacing on a USB keyboard
to a regular PC work? I look forward to your answer.

What you want to do cannot be done with current devices.

Unfortunately I have to disagree with you - a more likely reason seems

to me that you simply don't know enough about the USB specification to
give an answer. It would be disappointing to me if nobody in this
newsgroup can answer a very simple question about USB keyboard
interfacing.

This question is frequently asked in the Palm newsgroups and the answer is
always the same...
People in the Palm newsgroups are not exactly known for knowledge

about hardware...

More about me: http://www.jecarter.com/
VB3/VB6/C/PowerBasic source code: http://www.jecarter.com/programs.html
Freeware for the Palm with NS Basic source code: http://nsb.jecarter.com
Drivers for Pablo graphics tablet and JamCam cameras: http://home.earthlink.net/~mwbt/
johnecarter at@at mindspring dot.dot com. Fix the obvious to reply by email.

 

[Theo van der Merwe]

Bob Stephens <stephensyomamadigital@earthlink.net> wrote in message news:<6hg9vvwb4jyk.wikr6iqo7vxd$.dlg@40tude.net>...

On Thu, 18 Mar 2004 20:05:47 GMT, the Wiz wrote:

ntvdml@iafrica.com (Theo van der Merwe) wrote:

How do I interface common USB devices to a PDA? As I have recently
bought the entry level Palm Zire, I would at present be more
interested in the Palm PDA.

[snip]

In summary I want to know how USB interfacing works in detail so I can
interface some common USB devices to a PDA (I am assuming that USB
drivers for the Palm to common USB devices is not available?). I don't
need to develop an USB driver at this stage (which might be very
difficult?). Would it be possible to interface more than one USB
device to a PDA? If so, what changes in programming is required?

Best regards,
Theo van der Merwe (ntvdmREMOVE@iafrica.com)

USB is not a simple protocol like RS232, where the standard interface is
bi-directional.

The Palm is a USB slave device and cannot connect to other USB slave devices
(keyboard, etc).

What you want to do cannot be done with current devices.

This question is frequently asked in the Palm newsgroups and the answer is
always the same...

More about me: http://www.jecarter.com/
VB3/VB6/C/PowerBasic source code: http://www.jecarter.com/programs.html
Freeware for the Palm with NS Basic source code: http://nsb.jecarter.com
Drivers for Pablo graphics tablet and JamCam cameras: http://home.earthlink.net/~mwbt/
johnecarter at@at mindspring dot.dot com. Fix the obvious to reply by email.

Don't know if your Palm has compact flash slots, but I know of two
companies who make CF USB host adapters for PDA's.
RATOC has the CFU1U and Twin Paradox has the SolarExpress PDA.
They are intended to interface to standard HID and bulk storage devices.

At present the Palm Zire does not have compact flash slots, but it is

something to keep in mind in future. Do you perhaps know how the USB
drivers work - can one use the standard Windows 98 USB drivers?
I have had a look at http://www.twin-paradox.com/SEPDA.html and it
seems to use the 'Microsoft’s Windows Mobile 2003 Operating
System (Pocket PC 2003))', so I don't know if it will work on a Palm?

At http://www.interpocket.co.uk/ they claim standard USB devices can
be connected to a Sharp Zaurus™ or HP iPAQ™. It seems to
work with Linux only at present (Windows CE in preparation) - I am not
quite sure what they mean by this? Is it compatible with a standard HP
iPAQ and how does the USB drivers work?

good luck,


Bob

 

[Wim Ton]

"Theo van der Merwe" <ntvdml@iafrica.com> wrote in message
news:25af4009.0403182158.d42bd4b@posting.google.com...

the Wiz <look@message.body> wrote in message
news:<srvj50ljrvdu9nsiei6jk3l1qv1cdfbqmk@4ax.com>...
ntvdml@iafrica.com (Theo van der Merwe) wrote:

How do I interface common USB devices to a PDA? As I have recently
bought the entry level Palm Zire, I would at present be more
interested in the Palm PDA.

[snip]

In summary I want to know how USB interfacing works in detail so I can
interface some common USB devices to a PDA (I am assuming that USB
drivers for the Palm to common USB devices is not available?). I don't
need to develop an USB driver at this stage (which might be very
difficult?). Would it be possible to interface more than one USB
device to a PDA? If so, what changes in programming is required?

Best regards,
Theo van der Merwe (ntvdmREMOVE@iafrica.com)

USB is not a simple protocol like RS232, where the standard interface is
bi-directional.

The Palm is a USB slave device and cannot connect to other USB slave
devices
(keyboard, etc).

I am not sure I follow this - how does the Palm keyboard interface to
the Palm then? However, if I give you the benefit of doubt I can
rephrase the question and ask how does interfacing on a USB keyboard
to a regular PC work? I look forward to your answer.

The keyboard on my Palm Pilot plugs in the sync connnector, which is RS232 +
a TTL in and TTL out line. You may use something like the FT232 to interface
a Palm RS232 port to USB, but the Palm will be a slave. For master device
you may look at Cypress or Philips products, and get a microcontroller that
talks to th ePalm RS232 on one side and USB on the other side.

[snip]
Wim

 

[Theo van der Merwe]

the Wiz <look@message.body> wrote in message news:<36sk50to4t6ss5l3f3diqvspc349hamg3q@4ax.com>...

Bob Stephens <stephensyomamadigital@earthlink.net> wrote:

On Thu, 18 Mar 2004 20:05:47 GMT, the Wiz wrote:

ntvdml@iafrica.com (Theo van der Merwe) wrote:

How do I interface common USB devices to a PDA? As I have recently
bought the entry level Palm Zire, I would at present be more
interested in the Palm PDA.

[snip]

Don't know if your Palm has compact flash slots, but I know of two
companies who make CF USB host adapters for PDA's.
RATOC has the CFU1U and Twin Paradox has the SolarExpress PDA.
They are intended to interface to standard HID and bulk storage devices.

good luck,


Bob

PDA is, unfortunately, a generic term.

The only PDAs with CF slots are Windows CE devices. Most Palm devices have
SD/MMC slots.

The Ratoc page specifies the devices the USB card works with:

ˇ Compaq iPAQ with CF Jacket, PC Card Jacket.
ˇ Dell Axim
ˇ Fujitsu Pocket Loox

I am not sure I understand the above, for example the Compaq. Can one
interface standard USB devices such as USB keyboards, digital cameras
with USB interface and USB memory sticks to the Compaq? If so, does it
use the standard Windows 98 drivers?

Nothing for the Palm :-(

Thanks for the feedback.

More about me: http://www.jecarter.com/
VB3/VB6/C/PowerBasic source code: http://www.jecarter.com/programs.html
Freeware for the Palm with NS Basic source code: http://nsb.jecarter.com
Drivers for Pablo graphics tablet and JamCam cameras: http://home.earthlink.net/~mwbt/
johnecarter at@at mindspring dot.dot com. Fix the obvious to reply by email.

 

[Theo van der Merwe]

"Wim Ton" <wimton@blueyonder.co.uk> wrote in message news:<3ay6c.19657$F.9662@news-binary.blueyonder.co.uk>...

"Theo van der Merwe" <ntvdml@iafrica.com> wrote in message
news:25af4009.0403182158.d42bd4b@posting.google.com...
the Wiz <look@message.body> wrote in message
news:<srvj50ljrvdu9nsiei6jk3l1qv1cdfbqmk@4ax.com>...
ntvdml@iafrica.com (Theo van der Merwe) wrote:

How do I interface common USB devices to a PDA? As I have recently
bought the entry level Palm Zire, I would at present be more
interested in the Palm PDA.

[snip]

In summary I want to know how USB interfacing works in detail so I can
interface some common USB devices to a PDA (I am assuming that USB
drivers for the Palm to common USB devices is not available?). I don't
need to develop an USB driver at this stage (which might be very
difficult?). Would it be possible to interface more than one USB
device to a PDA? If so, what changes in programming is required?

Best regards,
Theo van der Merwe (ntvdmREMOVE@iafrica.com)

USB is not a simple protocol like RS232, where the standard interface is
bi-directional.

The Palm is a USB slave device and cannot connect to other USB slave
devices
(keyboard, etc).

I am not sure I follow this - how does the Palm keyboard interface to
the Palm then? However, if I give you the benefit of doubt I can
rephrase the question and ask how does interfacing on a USB keyboard
to a regular PC work? I look forward to your answer.

The keyboard on my Palm Pilot plugs in the sync connnector, which is RS232 +
a TTL in and TTL out line. You may use something like the FT232 to interface
a Palm RS232 port to USB, but the Palm will be a slave. For master device
you may look at Cypress or Philips products, and get a microcontroller that
talks to th ePalm RS232 on one side and USB on the other side.

[snip]
Wim
Thanks for the feedback on the hardware side. However, would your

suggestions enable one to interface standard USB devices (such as
keyboards, memory sticks) to a Palm?
I don't think any USB drivers are available for the Palm, so it seems
like one would have to monitor the USB lines to determine the
interfacing? That is why I am interested to know if standard USB
interfacing details to devices (such as USB keyboards) is available?

 

[Bob Stephens]

On 19 Mar 2004 03:08:11 -0800, Theo van der Merwe wrote:

the Wiz <look@message.body> wrote in message news:<36sk50to4t6ss5l3f3diqvspc349hamg3q@4ax.com>...
Bob Stephens <stephensyomamadigital@earthlink.net> wrote:

On Thu, 18 Mar 2004 20:05:47 GMT, the Wiz wrote:

ntvdml@iafrica.com (Theo van der Merwe) wrote:

How do I interface common USB devices to a PDA? As I have recently
bought the entry level Palm Zire, I would at present be more
interested in the Palm PDA.

[snip]

Don't know if your Palm has compact flash slots, but I know of two
companies who make CF USB host adapters for PDA's.
RATOC has the CFU1U and Twin Paradox has the SolarExpress PDA.
They are intended to interface to standard HID and bulk storage devices.

good luck,


Bob

PDA is, unfortunately, a generic term.

The only PDAs with CF slots are Windows CE devices. Most Palm devices have
SD/MMC slots.

The Ratoc page specifies the devices the USB card works with:

ˇ Compaq iPAQ with CF Jacket, PC Card Jacket.
ˇ Dell Axim
ˇ Fujitsu Pocket Loox

I am not sure I understand the above, for example the Compaq. Can one
interface standard USB devices such as USB keyboards, digital cameras
with USB interface and USB memory sticks to the Compaq? If so, does it
use the standard Windows 98 drivers?


No, unfortunately. You need a WINCE.NET driver. We were going to use a

ruggedized Pocket PC as a front end to an embedded microprocessor,
communicating via USB 2.0. After much research and deliberation we backed
off for the time being and are using RS232. None of the USB chip
manufacturers or PDA vendors supplied Pocket PC host side drivers, and we
don't have time or resources to roll our own just now. The Compact flash
host side adapters I mentioned previously will work with the existing WINCE
USB driver for standard HID (mouse, keyboard etc.) or bulk storage devices,
but not with custom chip sets like the Cygnal C8051f320 which we had
planned to use. Another way to go is to purchase the Jungo Device Driver
Development Kit for about $4K and adapt their examples to your needs.

Bob

Bob

 

[the Wiz]

ntvdml@iafrica.com (Theo van der Merwe) wrote:

the Wiz <look@message.body> wrote in message news:<srvj50ljrvdu9nsiei6jk3l1qv1cdfbqmk@4ax.com>...
ntvdml@iafrica.com (Theo van der Merwe) wrote:

How do I interface common USB devices to a PDA? As I have recently
bought the entry level Palm Zire, I would at present be more
interested in the Palm PDA.

[snip]

In summary I want to know how USB interfacing works in detail

For details, read the USB 1.1 or 2.0 specification.

If you want to interface USB devices to a PDA, look for a WinCE PDA that has USB
master capabilities.

Best regards,
Theo van der Merwe (ntvdmREMOVE@iafrica.com)

USB is not a simple protocol like RS232, where the standard interface is
bi-directional.

The Palm is a USB slave device and cannot connect to other USB slave devices
(keyboard, etc).

I am not sure I follow this - how does the Palm keyboard interface to
the Palm then? However, if I give you the benefit of doubt I can
rephrase the question and ask how does interfacing on a USB keyboard
to a regular PC work? I look forward to your answer.
What you want to do cannot be done with current devices.

Unfortunately I have to disagree with you - a more likely reason seems
to me that you simply don't know enough about the USB specification to
give an answer. It would be disappointing to me if nobody in this
newsgroup can answer a very simple question about USB keyboard
interfacing.

Check this page from a vendor of USB keyboards. They are in business to sell
their products, but they know the limitations of USB PDAs.
http://www.man-machine.com/fx100%20palm.htm
Their keyboards for the Palm devices make use of the universal connector
(serial, plus a couple of other lines).

This question is frequently asked in the Palm newsgroups and the answer is
always the same...
People in the Palm newsgroups are not exactly known for knowledge
about hardware...

Depends on the newsgroup - the same could be said for this one...

More about me: http://www.jecarter.com/
VB3/VB6/C/PowerBasic source code: http://www.jecarter.com/programs.html
Freeware for the Palm with NS Basic source code: http://nsb.jecarter.com
Drivers for Pablo graphics tablet and JamCam cameras: http://home.earthlink.net/~mwbt/
johnecarter at@at mindspring dot.dot com. Fix the obvious to reply by email.

 

[Theo van der Merwe]

Bob Stephens <stephensyomamadigital@earthlink.net> wrote in message news:<2ct0h2cks2u8$.1n32unlvg07ll.dlg@40tude.net>...

On 19 Mar 2004 03:08:11 -0800, Theo van der Merwe wrote:

the Wiz <look@message.body> wrote in message news:<36sk50to4t6ss5l3f3diqvspc349hamg3q@4ax.com>...
Bob Stephens <stephensyomamadigital@earthlink.net> wrote:

On Thu, 18 Mar 2004 20:05:47 GMT, the Wiz wrote:

ntvdml@iafrica.com (Theo van der Merwe) wrote:

How do I interface common USB devices to a PDA? As I have recently
bought the entry level Palm Zire, I would at present be more
interested in the Palm PDA.

[snip]

Don't know if your Palm has compact flash slots, but I know of two
companies who make CF USB host adapters for PDA's.
RATOC has the CFU1U and Twin Paradox has the SolarExpress PDA.
They are intended to interface to standard HID and bulk storage devices.

good luck,


Bob

PDA is, unfortunately, a generic term.

The only PDAs with CF slots are Windows CE devices. Most Palm devices have
SD/MMC slots.

The Ratoc page specifies the devices the USB card works with:

ˇ Compaq iPAQ with CF Jacket, PC Card Jacket.
ˇ Dell Axim
ˇ Fujitsu Pocket Loox

I am not sure I understand the above, for example the Compaq. Can one
interface standard USB devices such as USB keyboards, digital cameras
with USB interface and USB memory sticks to the Compaq? If so, does it
use the standard Windows 98 drivers?


No, unfortunately. You need a WINCE.NET driver. We were going to use a
ruggedized Pocket PC as a front end to an embedded microprocessor,
communicating via USB 2.0. After much research and deliberation we backed
off for the time being and are using RS232. None of the USB chip
manufacturers or PDA vendors supplied Pocket PC host side drivers, and we
don't have time or resources to roll our own just now. The Compact flash
host side adapters I mentioned previously will work with the existing WINCE
USB driver for standard HID (mouse, keyboard etc.) or bulk storage devices,
but not with custom chip sets like the Cygnal C8051f320 which we had
planned to use. Another way to go is to purchase the Jungo Device Driver
Development Kit for about $4K and adapt their examples to your needs.

Thanks for your feedback. Do you mean that the host side adapters

should work with any USB keyboard / mouse? What do you understand
under 'bulk storage devices'? More specifically, do you know if USB
memory sticks would be compatible?
How about interfacing hard disks to the PDA for bulk storage? I have a
USB to IDE adapter, but I don't suppose it will work on the PDA unless
one have a driver?

Bob

Bob

 

[Theo van der Merwe]

the Wiz <look@message.body> wrote in message news:<miqm50123hv8mvet8r2kgfc0qjd3pcjn87@4ax.com>...

ntvdml@iafrica.com (Theo van der Merwe) wrote:

the Wiz <look@message.body> wrote in message news:<srvj50ljrvdu9nsiei6jk3l1qv1cdfbqmk@4ax.com>...
ntvdml@iafrica.com (Theo van der Merwe) wrote:

How do I interface common USB devices to a PDA? As I have recently
bought the entry level Palm Zire, I would at present be more
interested in the Palm PDA.

[snip]

In summary I want to know how USB interfacing works in detail

For details, read the USB 1.1 or 2.0 specification.

Would that provide an answer to my question about the interfacing to a
keyboard and memory stick, or is the USB interfacing device dependent?

If you want to interface USB devices to a PDA, look for a WinCE PDA that has USB
master capabilities.

Any model PDA that springs to mind? A compact flash USB host adapter
was mentioned in this thread. Do you perhaps know how the USB drivers
for the device (e.g. USB keyboard, USB memory stick or hard disk)
would work?

Best regards,
Theo van der Merwe (ntvdmREMOVE@iafrica.com)

USB is not a simple protocol like RS232, where the standard interface is
bi-directional.

The Palm is a USB slave device and cannot connect to other USB slave devices
(keyboard, etc).

I am not sure I follow this - how does the Palm keyboard interface to
the Palm then? However, if I give you the benefit of doubt I can
rephrase the question and ask how does interfacing on a USB keyboard
to a regular PC work? I look forward to your answer.
What you want to do cannot be done with current devices.

Unfortunately I have to disagree with you - a more likely reason seems
to me that you simply don't know enough about the USB specification to
give an answer. It would be disappointing to me if nobody in this
newsgroup can answer a very simple question about USB keyboard
interfacing.

Check this page from a vendor of USB keyboards. They are in business to sell
their products, but they know the limitations of USB PDAs.
http://www.man-machine.com/fx100%20palm.htm
Their keyboards for the Palm devices make use of the universal connector
(serial, plus a couple of other lines).


This question is frequently asked in the Palm newsgroups and the answer is
always the same...
People in the Palm newsgroups are not exactly known for knowledge
about hardware...

Depends on the newsgroup - the same could be said for this one...

I am sorry to hear this - do you perhaps know of another newsgroup in
which I can find an answer to my question?

More about me: http://www.jecarter.com/
VB3/VB6/C/PowerBasic source code: http://www.jecarter.com/programs.html
Freeware for the Palm with NS Basic source code: http://nsb.jecarter.com
Drivers for Pablo graphics tablet and JamCam cameras: http://home.earthlink.net/~mwbt/
johnecarter at@at mindspring dot.dot com. Fix the obvious to reply by email.

 

[Bob Stephens]

On 19 Mar 2004 15:27:26 -0800, Theo van der Merwe wrote:

Bob Stephens <stephensyomamadigital@earthlink.net> wrote in message news:<2ct0h2cks2u8$.1n32unlvg07ll.dlg@40tude.net>...
On 19 Mar 2004 03:08:11 -0800, Theo van der Merwe wrote:

the Wiz <look@message.body> wrote in message news:<36sk50to4t6ss5l3f3diqvspc349hamg3q@4ax.com>...
Bob Stephens <stephensyomamadigital@earthlink.net> wrote:

On Thu, 18 Mar 2004 20:05:47 GMT, the Wiz wrote:

ntvdml@iafrica.com (Theo van der Merwe) wrote:

How do I interface common USB devices to a PDA? As I have recently
bought the entry level Palm Zire, I would at present be more
interested in the Palm PDA.

[snip]

Don't know if your Palm has compact flash slots, but I know of two
companies who make CF USB host adapters for PDA's.
RATOC has the CFU1U and Twin Paradox has the SolarExpress PDA.
They are intended to interface to standard HID and bulk storage devices.

good luck,


Bob

PDA is, unfortunately, a generic term.

The only PDAs with CF slots are Windows CE devices. Most Palm devices have
SD/MMC slots.

The Ratoc page specifies the devices the USB card works with:

ˇ Compaq iPAQ with CF Jacket, PC Card Jacket.
ˇ Dell Axim
ˇ Fujitsu Pocket Loox

I am not sure I understand the above, for example the Compaq. Can one
interface standard USB devices such as USB keyboards, digital cameras
with USB interface and USB memory sticks to the Compaq? If so, does it
use the standard Windows 98 drivers?


No, unfortunately. You need a WINCE.NET driver. We were going to use a
ruggedized Pocket PC as a front end to an embedded microprocessor,
communicating via USB 2.0. After much research and deliberation we backed
off for the time being and are using RS232. None of the USB chip
manufacturers or PDA vendors supplied Pocket PC host side drivers, and we
don't have time or resources to roll our own just now. The Compact flash
host side adapters I mentioned previously will work with the existing WINCE
USB driver for standard HID (mouse, keyboard etc.) or bulk storage devices,
but not with custom chip sets like the Cygnal C8051f320 which we had
planned to use. Another way to go is to purchase the Jungo Device Driver
Development Kit for about $4K and adapt their examples to your needs.

Thanks for your feedback. Do you mean that the host side adapters
should work with any USB keyboard / mouse? What do you understand
under 'bulk storage devices'? More specifically, do you know if USB
memory sticks would be compatible?
How about interfacing hard disks to the PDA for bulk storage? I have a
USB to IDE adapter, but I don't suppose it will work on the PDA unless
one have a driver?


Bob

Bob

My *guess* is that both the memory sticks and IDE adapters will work
provided they adhere to the USB spec and are recognized as mass storage
devices.

Bob -No warranty express or implied

 

[Theo van der Merwe]

Ian Stirling <root@mauve.demon.co.uk> wrote in message news:<Ikn6c.21287$h44.2572424@stones.force9.net>...

In sci.electronics.design Theo van der Merwe <ntvdml@iafrica.com> wrote:
How do I interface common USB devices to a PDA? As I have recently
bought the entry level Palm Zire, I would at present be more
interested in the Palm PDA.

More specifically, I have the following questions:

1) How does the interfacing to a regular USB keyboard work? I would
like to use a full size USB keyboard with the Palm Zire. It is not
necessary to develop a driver for the PDA, a simple application in
which one can type text (which can then be copied later to e.g.
memopad) is sufficient for my purposes.
snip
In summary I want to know how USB interfacing works in detail so I can
interface some common USB devices to a PDA (I am assuming that USB
drivers for the Palm to common USB devices is not available?). I don't
need to develop an USB driver at this stage (which might be very
difficult?). Would it be possible to interface more than one USB
device to a PDA? If so, what changes in programming is required?

It's hardware, not software.
The PDA would have to integrate a USB host, not just a USB device.
I don't think any do.
Thanks for your feedback. I am still confused by the concept of a USB

host. According to http://computer.howstuffworks.com/usb4.htm two
wires carry the data in the USB cable. The USB connectors are
different to encourage 'correct' use
(http://computer.howstuffworks.com/usb2.htm) - so that a 'Master'
(e.g. PC) is always connected to a 'Slave' (USB device). But this is
just a software issue as far as I can tell? As far as I can see
nothing would prevent a PC from becoming a 'Slave' device if the USB
software is updated (the typical role is a of course as a USB host)?
And a PDA could also become a 'Master' device if the software is
updated? Why would one need a CF USB host adapter - is it perhaps
simply modifying the USB signals to fool a 'USB device' into thinking
that it is a 'Master' (USB host), when the PDA is in fact usually
acting as a 'Slave'?
Or is there perhaps something in the hardware itself that I am missing
(the USB connector itself does not seem to have any information on
whether the device is a 'Master' or 'Slave')?

 

[Peter Bennett]

On 21 Mar 2004 16:26:09 -0800, ntvdml@iafrica.com (Theo van der Merwe)
wrote:

Thanks for your feedback. I am still confused by the concept of a USB
host. According to http://computer.howstuffworks.com/usb4.htm two
wires carry the data in the USB cable. The USB connectors are
different to encourage 'correct' use
(http://computer.howstuffworks.com/usb2.htm) - so that a 'Master'
(e.g. PC) is always connected to a 'Slave' (USB device). But this is
just a software issue as far as I can tell? As far as I can see
nothing would prevent a PC from becoming a 'Slave' device if the USB
software is updated (the typical role is a of course as a USB host)?
And a PDA could also become a 'Master' device if the software is
updated? Why would one need a CF USB host adapter - is it perhaps
simply modifying the USB signals to fool a 'USB device' into thinking
that it is a 'Master' (USB host), when the PDA is in fact usually
acting as a 'Slave'?
Or is there perhaps something in the hardware itself that I am missing
(the USB connector itself does not seem to have any information on
whether the device is a 'Master' or 'Slave')?

Based on my (limited) understanding, much of the USB communications
protocol is handled by a chip designed for that purpose, and not
directly by the host CPU. Some of these chips are designed as slaves,
and are not capable of acting as masters, regardless of what you do
with software on the host machine.

Please do a google for "USB protocol", and follow some of the links
you find - http://www2.rad.com/networks/2000/usb/indx.htm looks
useful, at a quick glance.





--
Peter Bennett, VE7CEI
peterbb (at) interchange.ubc.ca
new newsgroup users info : http://vancouver-webpages.com/nnq
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver.powersquadron.ca

 

[Theo van der Merwe]

Peter Bennett <peterbb@somewhere.invalid> wrote in message news:<b3fs509fmph7hv9voa2quf4bcrdkvbng8d@news.supernews.com>...

On 21 Mar 2004 16:26:09 -0800, ntvdml@iafrica.com (Theo van der Merwe)
wrote:

Thanks for your feedback. I am still confused by the concept of a USB
host. According to http://computer.howstuffworks.com/usb4.htm two
wires carry the data in the USB cable. The USB connectors are
different to encourage 'correct' use
(http://computer.howstuffworks.com/usb2.htm) - so that a 'Master'
(e.g. PC) is always connected to a 'Slave' (USB device). But this is
just a software issue as far as I can tell? As far as I can see
nothing would prevent a PC from becoming a 'Slave' device if the USB
software is updated (the typical role is a of course as a USB host)?
And a PDA could also become a 'Master' device if the software is
updated? Why would one need a CF USB host adapter - is it perhaps
simply modifying the USB signals to fool a 'USB device' into thinking
that it is a 'Master' (USB host), when the PDA is in fact usually
acting as a 'Slave'?
Or is there perhaps something in the hardware itself that I am missing
(the USB connector itself does not seem to have any information on
whether the device is a 'Master' or 'Slave')?


Based on my (limited) understanding, much of the USB communications
protocol is handled by a chip designed for that purpose, and not
directly by the host CPU. Some of these chips are designed as slaves,
and are not capable of acting as masters, regardless of what you do
with software on the host machine.

Thanks for the feedback. I am used to a protocol like RS232 in which

you can (in principle) implement any protocol with software.
Unfortunately it seems that the USB interface standard uses a fixed
protocol (implemented by a chip set)?
Because of hot swap capability, for most people only a single USB
device at a time would be sufficient. As such the full USB standard
seems to be a complete overkill. It seems to be very complicated to do
a simple task of communicating between two devices (meaning that only
people with resources can develop this standard)?
If all USB communication in a PDA is handled by a proprietary chipset,
then it would not seem possible to change a PDA to a host by software
control? This is in my opinion quite a silly situation - the idea
behind a PDA is (as far as I can see) to have a 'pocket sized'
computer available (which can act as a host to control other USB
devices). Of course to sync with a computer the PDA would have to be a
'Slave' device (which should be easy to do in a chipset?).

Please do a google for "USB protocol", and follow some of the links
you find - http://www2.rad.com/networks/2000/usb/indx.htm looks
useful, at a quick glance.
Thanks for the feedback.

 

[Ian Stirling]

In sci.electronics.design Theo van der Merwe <ntvdml@iafrica.com> wrote:
<snip>

Thanks for the feedback. I am used to a protocol like RS232 in which
you can (in principle) implement any protocol with software.
Unfortunately it seems that the USB interface standard uses a fixed
protocol (implemented by a chip set)?

Pretty much.
There is no reason it couldn't be done in software, it's just that the
protocol is so fast that it would require a dedicated CPU, especially
for higher speeds.
And it's much cheaper to use dedicated logic.

If all USB communication in a PDA is handled by a proprietary chipset,
then it would not seem possible to change a PDA to a host by software
control? This is in my opinion quite a silly situation - the idea
behind a PDA is (as far as I can see) to have a 'pocket sized'
computer available (which can act as a host to control other USB
devices). Of course to sync with a computer the PDA would have to be a
'Slave' device (which should be easy to do in a chipset?).

Unfortunately, reality doesn't care about what we think is silly.

However, there are reasons why it's challenging, apart from the
fact that it's not done.

Many PDAs have little memory.
What would a 8Mb device do with a 24Mb scanned picture.

Many PDAs simply cannot supply the current many USB devices will draw,
their batteries are too small (or the power converter which increases
in size weight and cost as power use goes up).
(most 2*AAA batteries simply cannot produce the 2.5W required by the standard
for more than moments)
There are some USB standards for interfacing, which are generally
followed for mice, keyboards and storage devices. (search for HID and
mass-storage)

Pretty much anything else requires a custom driver, and will often
make tradeoffs in the hardware assuming there is a fast CPU at the
other end.
These drivers are only typically written for one or two versions of windows,
and a few other operating systems if lucky.

However, there is a proposed (new?) standard for doing bidirectional stuff
for new hardware.
See http://www.usb.org/

It would indeed be handy, I'd like to be able to plug my camera into
my MP3 player, and save pictures.

 

[Theo van der Merwe]

Ian Stirling <root@mauve.demon.co.uk> wrote in message news:<LjA7c.22739$h44.2869201@stones.force9.net>...

In sci.electronics.design Theo van der Merwe <ntvdml@iafrica.com> wrote:
snip
Thanks for the feedback. I am used to a protocol like RS232 in which
you can (in principle) implement any protocol with software.
Unfortunately it seems that the USB interface standard uses a fixed
protocol (implemented by a chip set)?

Pretty much.
There is no reason it couldn't be done in software, it's just that the
protocol is so fast that it would require a dedicated CPU, especially
for higher speeds.

For some applications speed might be an issue, but I am perfectly
willing (while travelling of course) to wait longer for the transfer
of information (in other words for me it is not essential to
communicate at the full bandwith of the USB1.1 or USB2.0 spec). A
typical application would be to archive JPEG/MPEG movie files from a
digital camera to a hard disk (which I would hope could be connected
via an USB-IDE adapter!) in order to free up space on the memory
stick. It would not matter too much if the process took say 30 minutes
on the PDA instead of only 4 minutes on a PC. But unfortunately it
seems like one have no control over the USB ports (like one had with
the RS232) - you are forced to take it or leave it. For my application
I don't need very complicated protocol standards - I simply want to
archive the information easily while on move with the PDA (the
processing can be done later on a regular PC). So the memory stick
could be formatted as a linear sequence of bytes (the same with the
hard disk) and the complete contents of the memory stick could simply
be dumped to the next available block in the memory stick or hard
disk.

Maybe another option might be to investigate a RS232 to USB converter?
Another possibility could be an infrared to USB converter?

And it's much cheaper to use dedicated logic.
If all USB communication in a PDA is handled by a proprietary chipset,
then it would not seem possible to change a PDA to a host by software
control? This is in my opinion quite a silly situation - the idea
behind a PDA is (as far as I can see) to have a 'pocket sized'
computer available (which can act as a host to control other USB
devices). Of course to sync with a computer the PDA would have to be a
'Slave' device (which should be easy to do in a chipset?).

Unfortunately, reality doesn't care about what we think is silly.

Is 'reality' perhaps related to Mr. Bill Gates? The very complicated
USB standard certainly seems to stiffle competition...

However, there are reasons why it's challenging, apart from the
fact that it's not done.

Many PDAs have little memory.
What would a 8Mb device do with a 24Mb scanned picture.

Good question, but I was not specifically thinking of connecting a
scanner to a PDA (yet)! At present my interest is more in connecting a
digital camera (with mory stick) to a PDA.
For a PDA one would also like to have adequate room for archiving
information. The 2.5 inch IDE hard disks seems (or USB hard disks /
Microdrives) seems ideal for this purpose. Unfortunately the PDA and
hard disk are both 'Slave' devices, so they cannot communicate! How
silly...
Is there perhaps a way to implement the USB protocol using a serial to
USB converter? As mentioned previously I am not primarily interested
in performance (although the faster the better of course).

Many PDAs simply cannot supply the current many USB devices will draw,
their batteries are too small (or the power converter which increases
in size weight and cost as power use goes up).
(most 2*AAA batteries simply cannot produce the 2.5W required by the standard
for more than moments)

Supplying external power should pose no problems? Can a memory stick
really draw 2.5W?

There are some USB standards for interfacing, which are generally
followed for mice, keyboards and storage devices. (search for HID and
mass-storage)

Do you perhaps have a specific reference for USB memory sticks and USB
hard disks?

Pretty much anything else requires a custom driver, and will often
make tradeoffs in the hardware assuming there is a fast CPU at the
other end.
These drivers are only typically written for one or two versions of windows,
and a few other operating systems if lucky.

Finding a USB driver for a PDA seems highly unlikely?

However, there is a proposed (new?) standard for doing bidirectional stuff
for new hardware.
See http://www.usb.org/

Interesting - but is this different from making the device both a USB
host ('Master') and USB device ('slave'), perhaps with an option for
the user to choose which mode?
Is this perhaps going back to the concepts of the old RS232 (although
at a much faster potential transfer rate for USB)?

It would indeed be handy, I'd like to be able to plug my camera into
my MP3 player, and save pictures.

If your MP3 player is organized as a 'memory stick' I suppose that
should be possible in principle (the camera could be the USB host or
'Master' and the 'memory stick' the USB device or 'Slave, or vice
versa).

 

[Ian Stirling]

In sci.electronics.design Theo van der Merwe <ntvdml@iafrica.com> wrote:

Ian Stirling <root@mauve.demon.co.uk> wrote in message news:<LjA7c.22739$h44.2869201@stones.force9.net>...
In sci.electronics.design Theo van der Merwe <ntvdml@iafrica.com> wrote:
snip
Thanks for the feedback. I am used to a protocol like RS232 in which
you can (in principle) implement any protocol with software.
Unfortunately it seems that the USB interface standard uses a fixed
protocol (implemented by a chip set)?

Pretty much.
There is no reason it couldn't be done in software, it's just that the
protocol is so fast that it would require a dedicated CPU, especially
for higher speeds.

For some applications speed might be an issue, but I am perfectly
willing (while travelling of course) to wait longer for the transfer
of information (in other words for me it is not essential to
communicate at the full bandwith of the USB1.1 or USB2.0 spec). A

Nope.
You have to go at the bus speed (which may be only 1.5MBps) or nothing
will understand.

Maybe another option might be to investigate a RS232 to USB converter?
Another possibility could be an infrared to USB converter?

These are the wrong way round.
They add a serail port to a USB bus, NOT a USB bus to a serial port.
<snip>

Unfortunately, reality doesn't care about what we think is silly.


Is 'reality' perhaps related to Mr. Bill Gates? The very complicated
USB standard certainly seems to stiffle competition...

No it doesn't.
It's about as complex as it needs to be, to do all it needs to.
It's freely available, and downloadable by anything.

However, there are reasons why it's challenging, apart from the
fact that it's not done.

Many PDAs have little memory.
What would a 8Mb device do with a 24Mb scanned picture.

Is there perhaps a way to implement the USB protocol using a serial to
USB converter? As mentioned previously I am not primarily interested
in performance (although the faster the better of course).

No.

Many PDAs simply cannot supply the current many USB devices will draw,
their batteries are too small (or the power converter which increases
in size weight and cost as power use goes up).
(most 2*AAA batteries simply cannot produce the 2.5W required by the standard
for more than moments)

Supplying external power should pose no problems? Can a memory stick
really draw 2.5W?

No, not in this case.

There are some USB standards for interfacing, which are generally
followed for mice, keyboards and storage devices. (search for HID and
mass-storage)

Do you perhaps have a specific reference for USB memory sticks and USB
hard disks?

As I've said, go look at http://www.usb.org/

Pretty much anything else requires a custom driver, and will often
make tradeoffs in the hardware assuming there is a fast CPU at the
other end.
These drivers are only typically written for one or two versions of windows,
and a few other operating systems if lucky.


Finding a USB driver for a PDA seems highly unlikely?

They are not written for them, no.

However, there is a proposed (new?) standard for doing bidirectional stuff
for new hardware.
See http://www.usb.org/


Interesting - but is this different from making the device both a USB
host ('Master') and USB device ('slave'), perhaps with an option for
the user to choose which mode?
Yes, it's different.

You need to go and read the standards on http://www.usb.org/

Is this perhaps going back to the concepts of the old RS232 (although
at a much faster potential transfer rate for USB)?

No.

It would indeed be handy, I'd like to be able to plug my camera into
my MP3 player, and save pictures.

If your MP3 player is organized as a 'memory stick' I suppose that
should be possible in principle (the camera could be the USB host or
'Master' and the 'memory stick' the USB device or 'Slave, or vice
versa).