Example on how to use the USB control EndPoint EP0

[FrPo_1282226]

Hi there,

I need to be able to get control messages from the EP0.

I'm using a PSoC 5LP, and I can successfully read and Write USB messages on EP1 and EP2.

For compatibility reason I need to use the Endpoint 0 to configure the PSOC.

I have tried the following code, but is not working:

#define EP0 0

uint8_t  NewUSBMessage()

{

  uint8_t retVal;

    retVal =0;

    if (USB_bGetEPState(EP0)!= USB_OUT_BUFFER_EMPTY)

    {

        USB_ReadOutEP(EP0,Message,length);

        retVal = 1;

    }

    return retVal;

}

Can somebody help me please? send me some example link, etc.

Thanks,

Francesco

[Len_CONSULTRON · Accepted solution]

Francesco,

I'm not a USB configuration expert but here goes:

I'm assuming NewUSBMessage() is an ISR you want called when EP0 is activated.

You may need to make the following changes if you already haven't:

Rename the function NewUSBMessage() to <comp_name>_EP_0_ISR_ExitCallback()

Add the following lines into file cyapicallbacks.h:

#define <comp_name>_EP_0_ISR_EXIT_CALLBACK
void <comp_name>_EP_0_ISR_ExitCallback();

Note: <comp_name> needs to be substituted with the name of your USBFS component.

I've used USBFS and EP0 and these are the changes I had to add to get EP0 to be processes with my own code.

Len

[FrPo_1282226]

Thank you Len!

it worked!

I'm writing the solution in case other people need it.

In order to read the messages from EP0 I have added

      #define USB_EP_0_ISR_EXIT_CALLBACK 

     void USB_EP_0_ISR_ExitCallback();

in cyapicallback.h

and I wrote this function:

void USB_EP_0_ISR_ExitCallback(){

    int length = USB_currentTD.count;   

         if (length == 😎

             for (int i = 0; i< length; i++)

             {

                    Message = USB_currentTD.pData;

             }

}

which seems working.

Now I'm having the opposite problem  I can't sens (anymore) data to the IN EP1).

the PSoC 

// wait until our IN Endpoint is empty

            while(USB_GetEPState(UNDPOINTIN) != USB_IN_BUFFER_EMPTY);

Do you know what else could be wrong now?

Thank you!

[Ekta_N]

Hello Francesco,

For the functions like USBFS_ReadOutEP(), the valid value of endpoint number ranges from 1 to 8. You cannot give 0 for the endpoint number parameter in it.

As already mentioned by Len you can use the USBFS_EP_0_ISR_ExitCallback() and USBFS_EP_0_ISR_EntryCallback() ISR's located in the USBFS_dvrc.c . These ISR's are triggered to handle control transfers directed to endpoint.

To use these ISRs you need to define  USBFS_EP_0_ISR_ENTRY_CALLBACK (or USBFS_EP_0_ISR_EXIT_CALLBACK) in the cyapicallbacks.h as shown in the image below:

Then define the USBFS_EP_0_ISR_EntryCallback() function in the main.c to perform the desired function.

Regards

Ekta