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HID Feature Report parse error with Windows HID Sensor driver

Jay Jones
Intellectual 330 points

My feature report generates a "HID Feature parse error" when I send more than 4 wide-characters in the HID_USAGE_PROPERTY_SERIAL_NUMBER.  I've tested by increasing the feature desriptor and feature report as needed to send from 1 to 12 characters and by descresing as needed to send from 12 to 1 characters.

For a 1 to 4 characters serial number, the device, Windows Sensor Driver and Windows Client App behave as expected,with idle timeout, advertising, reconnecting, resending the serial number  and sensor data without problems.

For a 5 character serial number, the device connects, sends the serial number and data, and idle timeouts but on reconnect, the Windows Driver reports an HID Feature Report parse error.  The device is then disconnected.

For a >5 character serial number, the device advertises but generates a "Power failure" message.

I've not found any examples of using the BLESTACK with the Windows 8 Sensor Driver.  I suspect a HID feature related buffer problem and I've installed the SMARTRF Packet sniffer.

As anyone seen this problem?

  • 0
    Intellectual 330 points

    Update:

    I removed all of the properties from the Feature Report descriptor except for the serial number to determine the largest string I could send to the Windows Sensor Driver/Sensor Diagnostic Tool (SDT). 

    The maximum length for normal operation between my sensor and the SDT was 8 wide characters and 1 wide terminator, for 9 wide characters (18 bytes). 

    9 wide characters and 1 wide terminator (10 wide characters) allowed initial connection with the correct string sent to the SDT.  But after idle timeout and reconnect, the Sensor Driver reported a HID Feature Parse error.

    11 or more characters (counting terminator) did not allow initial connection.

    It appears that the maximum feature report size allowed by the BLESTACK API is 18 bytes (which is consistent with the max allowed feature report size from previous testing with other properties in the feature report).  According to the HID feature report specifications, the max feature report size is 64 bytes.

    I appreciate any help in increasing the size of the feature report in BLESTACK API.  I am using version 1.3.3.  I'll check 1.4 release notes to see if this issue is listed.

    Jay