Question about the USBFS component of psoc5lp

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YaIs_283501
Level 3
Level 3
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The maximum packet size of the endpoint is 64 bytes in the CDC interface of the USBFS component. If the received data may exceed 64 bytes, is it impossible to process the data received by the endpoint interrupt? Is it necessary to process the receive buffer by polling if the receive string exceeds 64 bytes?

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AnkitaS_51
Employee
Employee
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Hello,

As per the specification the CDC interface need the data endpoints as Bulk endpoint only. The bulk endpoint has limitation on the packet size of  64 bytes as per the USB Full speed specification.

The CDC data can be accessed using API(OUT packet).

You have to receive data in chunks of 64 bytes (like by polling) and process accordingly.

Please check this KBA when you try to send 64 bytes/Maximum Payload Size Packet in USBUART componenet:

Problem in Sending 64 bytes / Maximum Payload Size Packet in USBUART Component – KBA89052

These links may be useful:

https://stackoverflow.com/questions/4813368/usb-polling-mechanism

PSoC5LP - How to send longer lines than USB CDC maximum packet size

Looking for advice on using USBUART in an interrupt driven mannor on the PSoC5LP

Thanks,

Ankita

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AnkitaS_51
Employee
Employee
100 likes received 50 likes received 25 likes received

Hello,

As per the specification the CDC interface need the data endpoints as Bulk endpoint only. The bulk endpoint has limitation on the packet size of  64 bytes as per the USB Full speed specification.

The CDC data can be accessed using API(OUT packet).

You have to receive data in chunks of 64 bytes (like by polling) and process accordingly.

Please check this KBA when you try to send 64 bytes/Maximum Payload Size Packet in USBUART componenet:

Problem in Sending 64 bytes / Maximum Payload Size Packet in USBUART Component – KBA89052

These links may be useful:

https://stackoverflow.com/questions/4813368/usb-polling-mechanism

PSoC5LP - How to send longer lines than USB CDC maximum packet size

Looking for advice on using USBUART in an interrupt driven mannor on the PSoC5LP

Thanks,

Ankita

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thank you for your advice.

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