Could not send 64 bytes of data through K20 USB

[d_dinesh_k]

Hi,

I am using  Kinetis K20 USB for data transfer but while trying to send exactly 64 bytes of data from K20, the data is not being sent out of USB. On sending less than 64 bytes of data, the data transfer is working fine. 

Is there any limitation on sending data at 64 bytes in K20 USB ?

Regards,

Dinesh Kumar  

[mjbcswitzerland]

Hi Dinesh 

If you are using 64byte endpoints to send data over an endpoint of length 64 you probably need to send an addition a zero length frame for that the USB host understands that the "complete" date has been received and should be processed.

Very probably the data has been sent but your host is not yet treating it - this is typical of USB-CDC, for example, and USB stacks that don't do this automatically for the user.

Regards

Mark

Complete K20 solutions, training and support:http://www.utasker.com/kinetis.html
Kinetis K20:
- http://www.utasker.com/kinetis/FRDM-K20D50M.html
- http://www.utasker.com/kinetis/TWR-K20D50M.html
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- http://www.utasker.com/kinetis/TEENSY_3.1.html
- http://www.utasker.com/kinetis/tinyK20.html
USB: http://www.utasker.com/docs/uTasker/USB_User_Guide.PDF
USB composites: http://www.utasker.com/kinetis/USB_Device.html
USB-CDC host<->device video: https://www.youtube.com/watch?v=XhISV1czIo4&list=PLWKlVb_MqDQFZAulrUywU30v869JBYi9Q&index=16