Hello Everyone,
I need to develop a USB device driver. this is first time i'm working on USB protocol.
Hardware information: this is a customized board using LPC1837 controller, which two USB ports. but we are using only one USB. i'm using CMSIS USB driver to develop the code.
Compiler information: keil 5 vision
Software Information: i'm using CMSIS USB driver to develop the code.
the problem what i'm facing is when i connect my device to PC it display a message saying unknown device connected. can anyone help me out to resolve this problem.
little information about the steps or procedure i have followed.
i have gone through the USB protocol. the protocol has 4 types of packets.
1. Token
2. Data
3. Handshake
4. SOF(start of frame).
i have been sending the information of DEVICE_DESCRIPTOR which contains PID and VID data, by setting the
below is the Token struct which is sending the data to PC
usb_Token.sync = 0x55;
usb_Token.pid=0x1E;
usb_Token.Addr = 0x01;
usb_Token.endpoint=0x01;
usb_Token.CRC5 =0x05;
usb_Token.EOP=00;
below is the data struct which is sending the data of device descriptor
usb_data.sync=0x55;
usb_data.pid=0xB4;
usb_data.Data = (uint8_t *)device0_dev_desc;
usb_data.CRC16 = 0x12;
usb_data.EOP=0x00;
both the above struct was send one after the other using CMSIS API called endpoint Transfer.
USBDDrv->EndpointTransfer(0x80,(uint8_t *)&usb_Token,6);
USBDDrv->EndpointTransfer(0x80,(uint8_t *)&usb_data,22);
if anyone need i can provide the code.
