USB transferring data in a composite device (DUAL CDC)

[moulay-hassan]

Posted on May 30, 2016 at 08:30

I have emulated two VCPs with only one USB Device. I can send data in one VCP that has the following Endpoint Address.

#define CDC_IN_EP 0x81 /* EP1 for data IN */#define CDC_OUT_EP 0x01 /* EP1 for data OUT */#define CDC_CMD_EP 0x82 /* EP2 for CDC commands */

I would like to know if it's possible to send data in the other VCP with other Endpoint Address like :

#define CDC_IN_EP3 0x83 /* EP3 for data IN */#define CDC_OUT_EP3 0x03 /* EP3 for data OUT */#define CDC_CMD_EP4 0x84 /* EP4 for CDC commands */

My problem is that addresses others than 0x81 don't allow me to send data over the second VCP. I'm using two CDC interfaces Full-Speed. Normally we can use 7 endpoints with CDC_FS and that's what I'm trying to do.. I have 6 Endpoints: 3 for each VCP and the seventh is Endpoint 0 for configuration.

Have I missed something in the Endpoints Configuration or in the Composite Device Descriptors ?

Thank you guys.

#usb #stm32 #usb #cdc #cdc #vcp #endpoints

[Walid FTITI_O]

Posted on May 30, 2016 at 16:28

Hi el_alaoui.moulay_has,

USB CDC spec allow no more than one IN endpoint at single Communication Data class interface. Refer to this

https://my.st.com/public/STe2ecommunities/mcu/Lists/STM32Java/Flat.aspx?RootFolder=https://my.st.com/public/STe2ecommunities/mcu/Lists/STM32Java/Is%20it%20Possible%20for%20multiple%20IN%20bulk%20endpoints%20in%20CDC&FolderCTID=0x01200200770978C69A1141439FE559EB459D758000F9A0E3A95BA69146A17C2E80209AD...

for more information -Hannibal-

[moulay-hassan]

Posted on May 31, 2016 at 08:48 The original post was too long to process during our migration. Please click on the provided URL to read the original post. https://st--c.eu10.content.force.com/sfc/dist/version/download/?oid=00Db0000000YtG6&ids=0680X000006I6Wh&d=%2Fa%2F0X0000000bpy%2FslcbqW7OdA9Dm3bdhbXBZhQldPvLSQELwrrFyQrx1YY&asPdf=false