what is a PID Encoding Error?
If you suggested that the last four bits of the PID didn’t match the inverse of the first four bits then you would be right. Most functions will have a series of buffers, typically 8 bytes long. Each buffer will belong to an endpoint – EP0 IN, EP0 OUT etc. Say for example, the host sends a device descriptor request. The function hardware will read the setup packet and determine from the address field whether the packet is for itself, and if so will copy the payload of the following data packet to the appropriate endpoint buffer dictated by the value in the endpoint field of the setup token. It will then send a handshake packet to acknowledge the reception of the byte and generate an internal interrupt within the semiconductor/micro-controller for the appropriate endpoint signifying it has received a packet. This is typically all done in hardware. The software now gets an interrupt, and should read the contents of the endpoint buffer and parse the device descriptor request. Endpoints En
