Connecting microcontroller and pda with USB

Hello, is it possible to connect a pda, as a Palm, with a microcontroller using the usb port on the pda and a usb-to-serial conversion circuit on the micro?

Reply to
gidesa
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My understanding is that most pda's are USB slave devices and can not host another USB slave device such as a usb-to-serial adaptor. There are some USB device called "USB to go" that have a limited ability to host another USB device, but that is not the norm.

-Wayne

Reply to
Wayne C. Gramlich

But this can be the answer: If you use a microcontroller with "USB to go" functionality (AFAIR there is a AVR with such a USB interface on-chip) and make the microcontroller the host for the Palm, you're close to what the OP wants...

Reply to
Jens Peter Lindemann

There are a couple books that have been written about using PDAs in robots. I have two of them and I think one is called PDA robotics. I can't remember how exactly they did it, if they used the usb port or not. I will have to look it up later.

You may also want to check out

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they have some PDA robot kits that are pretty cool.

Joe McKibben

Reply to
Joe McKibben

At least acroname used to sell a PDA kit, it seems they don't have it any more. They used to have an omnidirectional robot that came with the PDA and everything.

Joe McKibben

Reply to
Joe McKibben

MicroSeeker used to use a Dell Axim PDA running Squeak, talking to a PIC microcontroller. I used a 19,200 baud serial link (RS-232) between them.

Right now, I'm using a gumstix verdex (which has host USB) running Squeak to talk through an FT232 USB transceiver chip to an ATmega168 at 1.0 Mbps. In Squeak I open the USB port as though it was a serial port, and everything works great.

Later, Jon

-------------------------------------------------------------- Jon Hylands snipped-for-privacy@huv.com

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Project: Micro Raptor (Small Biped Velociraptor Robot)
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Reply to
Jon Hylands

The book _PDA_Robotics_ by Doublas Williams (ISBN 0-7-141741-9) uses an IRDA interface to communicate with the rest of the robot. Old PDA's have IRDA's but newer ones have dropped that interface entirely in favor of USB.

Could you be more specific?

-Wayne

Reply to
Wayne C. Gramlich

Jon:

Your experience is not matching mine.

I am only having so-so success with my FTDI USB-to-RS232 serial converter. I need to do some more research, but it looks like there is some serious overhead in the USB protocol stack that adds some significant delays. I am running at 115200 and I am getting pathetic performance. My commands are really short -- send one or two bytes and get 1-3 bytes in return. I need to do some more sluething to verify that it is some stupid software bug tho'.

In a week or two I hope to have some more solid numbers as to what is really happening. (I need to order some more parts.)

-Wayne

Reply to
Wayne C. Gramlich

The other book I have is The Ultimate Palm Robot. It seems to give the same type of setup as PDA Robotics does.

Yeah Acroname's PPRK robot used to have a kit that hooked up to a PDA through there brainstem controller.

Joe McKibben

Reply to
Joe McKibben

It must be something you're doing. I know with at least one C++ library a friend was using, he was getting pathetic performance because the library was doing a 100 ms delay/timeout on every receive.

(update - I just asked him, and he said it was the lserie library from cppfrance, or something like that)

I can send and receive at 1,000,000 baud with no trouble, with very little delay. From windows, I get approximately 1-2ms of overhead with each round trip (after I reset the port latency to 1ms from its default 16ms).

The packets I send are between 10 and 150 bytes each, and receive packets are typically 10-15 bytes.

Later, Jon

-------------------------------------------------------------- Jon Hylands snipped-for-privacy@huv.com

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Project: Micro Raptor (Small Biped Velociraptor Robot)
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Reply to
Jon Hylands

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