USB enumeration for multiple interfaces

[Frank_D]

We are using a Kinetis K20 120MHz device with MQX 4.0 with all updates and are usig the USB Host function to try to connect to a device (cellular modem) that has multiple CDC interfaces. We are trying to use the MQX CDC host example code to connect to this device. The issue is that the MQX stack uses the last interface presented by the device during enumeration. We need to communicate over just one set of endpoints that happen not to be the last ones selected by the Host software during enumeration. We need to use endpoint 4 but the host enumerates with endpoint 10. Is there a way to manually set the endpoint after enumeration that the MQX USB host stack uses to communicate? Can anyone point me the USB Host API functions they would need to use?

[CarlosCasillas]

Hello Frank,

The CDC Host example is intended for establishing connection with single Interface Devices. I’m afraid that there is not available a specific example with this kind of devices; however, the “Freescale MQX USB Host API Reference Manual” document provides guidelines for the Host functions usage. In case of the CDC class, you could refer to chapters 5.2 and 6.4 of the mentioned document, which is available at the following path, considering MQX default installation paths:

C:\Freescale\Freescale_MQX_4_0\doc\usb\MQXUSBHOSTAPIRM.pdf

Hope this will be useful for you.

Best regards!

/Carlos