STM32F4 USB Polling interval

[massimiliano2]

Posted on June 22, 2016 at 06:58

Hello,

Using the processorSTMF401VETx I generate the project with STM Cube:

STMCube Mx version4.12.0

library STM32CubeFW_F4 v.1.10.0

I used the midlewarelibraries included in the framework to develop a USB HID device.

A little descriptionof my system:

USB Custom HID.

In the custom HIDpart the maximun packet size is 64Bytes (report id included) definedusing this constants.

&sharpdefineCUSTOM_HID_EPIN_SIZE 0x40

&sharpdefineCUSTOM_HID_EPOUT_SIZE 0x40

In the DeviceConfiguration Description the polling interval for the input and alsofor the output interval are set by defautl with 32ms.

It has an input andan output report both of them with 10 bytes lenght.

The device shouldsend every 10ms a status report (10 bytes).

The output reportsare received in interrupt mode.

Device comunicatewith a Windows' application that I have develop or with with a thirdparty, using the HID interface.

In that situation myapplication works fine but the third party application has a sloweddown behaviour.

Here is my problem:If I set the interrupt polling init with a value lower than 32ms theWindows' app work with a normal speed for a limited period and thenget totally hanged. In this situation the device is still working andit continues sending its state report but it can not receiveanything. When the Windows' application is blocked if I unplug andplug the device, the application recover its normal state until itgets blocked again like the firts time.

Endpoint Descriptor 81 1 In, Interrupt, 32 ms

EndpointDescriptor 01 1 Out, Interrupt, 32 ms

</colgroup>

Offset

Field

Size

Value

Description

0

bLength

1

07h

1

bDescriptorType

1

05h

Endpoint

2

bEndpointAddress

1

81h

1 In

3

bmAttributes

1

03h

Interrupt

1..0: Transfer Type

......11 

Interrupt

7..2: Reserved

000000.. 

4

wMaxPacketSize

2

0040h

64 bytes

6

bInterval

1

20h

32 ms

First i tried tomake smaller the MaxPacketSize in both endpoints, but the problesstill remains.

Then I searched inthe FW release notes for possibly fixes issues and I found this fixederror in version 4.13 release

343224 [USB CDC] usb_cdc_if.c receive function needs update to detectreceived packets

But after porting myprojecto to the newest version

STM Cube Mxversione 4.15.1

library STM32CubeFW_F4 v.1.12.0

the problem stillpersists, so it does not refer to this problem

Kind RegardsMax </colgroup>

Offset

Field

Size

Value

Description

0

bLength

1

07h

1

bDescriptorType

1

05h

Endpoint

2

bEndpointAddress

1

01h

1 Out

3

bmAttributes

1

03h

Interrupt

1..0: Transfer Type

......11 

Interrupt

7..2: Reserved

000000.. 

4

wMaxPacketSize

2

0040h

64 bytes

6

bInterval

1

20h

32 ms

#stm32f4-usb-polling-interval