STM32CubeMX USB control request

[Ted NIVAN]

Posted on September 11, 2017 at 21:16

Hi there,

I am using STM32CubeMX to develop a USB HID touchscreen with the STM32F103C8T6 MCU.

In the HID descriptor, I must report the following feature to support multi-touch:

 0x85, REPORTID_MAX_COUNT, // REPORT_ID (Feature)
 0x09, 0x05, // USAGE(Contact Count Maximum)
 0x95, 0x01, // REPORT_COUNT (1)
 0x25, 0x02, // LOGICAL_MAXIMUM (2)
 0xb1, 0x02, // FEATURE (Data,Var,Abs)

Which function should I use to do a USB control request as feature request?

#stm32-hid-usb #usb-hid-getfeature-setfeature #stm32f103c8t6 #usb-hid #stm32cubemx(hal)

[John Lee_O]

Posted on September 12, 2017 at 09:12

Hello,

You can generate a CustomHID project from CubeMX and modify the existing report descriptor(CUSTOM_HID_ReportDesc_FS[]) in 'usbd_custom_hid_if.c'. Than the report descriptor will be transmitted during the enumeration process automatically.

[Ted NIVAN]

Posted on September 12, 2017 at 12:18

Thanks for replying John.

I am able to create a report descriptor and transmit it but the point is that I don't know how to send feature report over usb (which function to use).

For this part of the descriptor:

 0x85, REPORTID_MAX_COUNT, // REPORT_ID (Feature)
 0x09, 0x05, // USAGE(Contact Count Maximum)
 0x95, 0x01, // REPORT_COUNT (1)
 0x25, 0x02, // LOGICAL_MAXIMUM (2)
 0xb1, 0x02, // FEATURE (Data,Var,Abs)

I must transmit the following structure:

static

const

uint8_t

hid_feature_report[] = {

0x02

,

//

report id

0x05

//

number of contact points

};

My question is: Which function should I use to respond to GET_REPORT(feature) requests?

In the HID1_pdf documentation, it is written that:

Only Input reports are sent via the Interrupt In pipe. Feature and

Output reports must be initiated by the host via the Control pipe or an optional Interrupt Out pipe.

[John Lee_O · Accepted solution]

Posted on September 13, 2017 at 05:08

Ah, I misunderstood your question. 

I think if the 'Feture report' were sent via contol pipe as described in HID1_11 document, following function would be used.

  - USBD_CtlSendData (USBD_HandleTypeDef *pdev, uint8_t *pbuf, uint16_t len)

And it need to be added as class specific request in USBD_CUSTOM_HID_Setup() function like below.

I hope this works for you .

[Ted NIVAN]

Posted on September 19, 2017 at 00:43

Yes I've finally found out. I should have told you.

What you wrote is exactly what I've done and it worked like a charm.

Thanks for your help though!