ctrl_transfer

[brksnn]

Hi,

I am working on UNI-T UT372 Tachometer and I want to understand how you specify the parameters of ctrl_transfer.

Your parameters;
bmRequestType = 0x21 #0b00100001 #Host to Device
bmRequest = 9
wValue = 0x0300 # Report Type
wIndex = 0 # interface
payload = message = [0x00, 0x4b, 0x00, 0x00, 0x03]

I also cheking this parameters from the following link.
http://www.usb.org/developers/hidpage/HID1_11.pdf

The request type is from host to device but I just want to read from device. Thus it should be 0xA1 (0b10100001). Also, Request should change. However, I am getting pipe error.

Can you inform me in detail, please? Especially, the message array?

Best,