/* * * DATA FORMAT * * IN Endpoint * * The device reserves the first two bytes of data on this endpoint to contain * the current values of the modem and line status registers. In the absence of * data, the device generates a message consisting of these two status bytes * every 40 ms. * * Byte 0: Modem Status * NOTE: 4 upper bits have same layout as the MSR register in a 16550 * * Offset Description * B0..3 Port * B4 Clear to Send (CTS) * B5 Data Set Ready (DSR) * B6 Ring Indicator (RI) * B7 Receive Line Signal Detect (RLSD) * * Byte 1: Line Status * NOTE: same layout as the LSR register in a 16550 * * Offset Description * B0 Data Ready (DR) * B1 Overrun Error (OE) * B2 Parity Error (PE) * B3 Framing Error (FE) * B4 Break Interrupt (BI) * B5 Transmitter Holding Register (THRE) * B6 Transmitter Empty (TEMT) * B7 Error in RCVR FIFO * * * OUT Endpoint * * This device reserves the first bytes of data on this endpoint contain the * length and port identifier of the message. For the FTDI USB Serial converter * the port identifier is always 1. * * Byte 0: Port & length * * Offset Description * B0..1 Port * B2..7 Length of message - (not including Byte 0) * */