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Start up problem with isochronous usb transfer.

emil83
Associate
Posted on May 03, 2012 at 15:23

Hello,

We are two swedish students trying to implement a camera unit into a circuit board. The company we're writing this report for has developed this platform and our task is to write a protocol that handles the video stream of data coming from a simple webcam (usb connection).

Our main focus for now is to write the code needed to ''wake the camera up''. Trying to get the start up commands ready and then configure the isochronous pipeline needed for the data transmit. We've been reading most guides available on the entire internet but we're still confused of how to do this... We've managed to set bits to different data registers and understand what an endpoint is, but thats pretty much it. 

So our question is, where do we start? What needs to be done to get the isochronous pipeline camera-->platform up and running?

We do understand that the answer we're looking for isnt that easy to print down in a line or two, but any info would be very appreciated.

We're using Eclipse Platform along with FreeRTOS.

Many thanks in advance.

Emil and Per
4 REPLIES 4
alok472
Associate II
Posted on May 04, 2012 at 19:13

It's not very clear if you want to implement on device side : USB Video Class. That is required for transfer of images from the camera to PC..

or you want to implement the host side. Where the webcam is conencted to STM32F107 / 207 usb-otg-host port ? Pls clarify

emil83
Associate
Posted on May 05, 2012 at 11:15

Thanks for your reply!

It looks like our

STM32F103 VCT6 board does not support OTG, so no wonder we cant get it to work.

USB is therefor off the table and instead we make this projekt abit more simple by using a JPEG camera ( 

http://www.sparkfun.com/products/10061

 ). Will make the programming alot easier, but i doubt we will have the baudrate needed in the UART-port to make a ''video transfer''. 

However, thats another problem and we may ask for helt further on in the project, if needed.

Thanks!

Posted on May 05, 2012 at 13:58

There is always the STM32F4 Discovery board, it is cheap and has OTG

http://www.st.com/internet/evalboard/product/252419.jsp

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alok472
Associate II
Posted on May 08, 2012 at 03:36

STM32F107 and STM32F207 and F407 have USB OTG functionality.

What you wanna do doesnt need USB OTG. The standard usb of STM32F103 is good enough.

i can confirm the UART baud rate is very fast (i used 115200). you only need ''Default baud rate of serial port is 38400 ''