| /* SPDX-License-Identifier: GPL-2.0 */ |
| /* |
| * Driver definitions for the FTDI USB Single Port Serial Converter - |
| * known as FTDI_SIO (Serial Input/Output application of the chipset) |
| * |
| * For USB vendor/product IDs (VID/PID), please see ftdi_sio_ids.h |
| * |
| * |
| * The example I have is known as the USC-1000 which is available from |
| * http://www.dse.co.nz - cat no XH4214 It looks similar to this: |
| * http://www.dansdata.com/usbser.htm but I can't be sure There are other |
| * USC-1000s which don't look like my device though so beware! |
| * |
| * The device is based on the FTDI FT8U100AX chip. It has a DB25 on one side, |
| * USB on the other. |
| * |
| * Thanx to FTDI (http://www.ftdichip.com) for so kindly providing details |
| * of the protocol required to talk to the device and ongoing assistence |
| * during development. |
| * |
| * Bill Ryder - bryder@sgi.com formerly of Silicon Graphics, Inc.- wrote the |
| * FTDI_SIO implementation. |
| * |
| */ |
| |
| /* Commands */ |
| #define FTDI_SIO_RESET 0 /* Reset the port */ |
| #define FTDI_SIO_MODEM_CTRL 1 /* Set the modem control register */ |
| #define FTDI_SIO_SET_FLOW_CTRL 2 /* Set flow control register */ |
| #define FTDI_SIO_SET_BAUD_RATE 3 /* Set baud rate */ |
| #define FTDI_SIO_SET_DATA 4 /* Set the data characteristics of |
| the port */ |
| #define FTDI_SIO_GET_MODEM_STATUS 5 /* Retrieve current value of modem |
| status register */ |
| #define FTDI_SIO_SET_EVENT_CHAR 6 /* Set the event character */ |
| #define FTDI_SIO_SET_ERROR_CHAR 7 /* Set the error character */ |
| #define FTDI_SIO_SET_LATENCY_TIMER 9 /* Set the latency timer */ |
| #define FTDI_SIO_GET_LATENCY_TIMER 0x0a /* Get the latency timer */ |
| #define FTDI_SIO_SET_BITMODE 0x0b /* Set bitbang mode */ |
| #define FTDI_SIO_READ_PINS 0x0c /* Read immediate value of pins */ |
| #define FTDI_SIO_READ_EEPROM 0x90 /* Read EEPROM */ |
| |
| /* Channel indices for FT2232, FT2232H and FT4232H devices */ |
| #define CHANNEL_A 1 |
| #define CHANNEL_B 2 |
| #define CHANNEL_C 3 |
| #define CHANNEL_D 4 |
| |
| |
| /* |
| * BmRequestType: 1100 0000b |
| * bRequest: FTDI_E2_READ |
| * wValue: 0 |
| * wIndex: Address of word to read |
| * wLength: 2 |
| * Data: Will return a word of data from E2Address |
| * |
| */ |
| |
| /* Port Identifier Table */ |
| #define PIT_DEFAULT 0 /* SIOA */ |
| #define PIT_SIOA 1 /* SIOA */ |
| /* The device this driver is tested with one has only one port */ |
| #define PIT_SIOB 2 /* SIOB */ |
| #define PIT_PARALLEL 3 /* Parallel */ |
| |
| /* FTDI_SIO_RESET */ |
| #define FTDI_SIO_RESET_REQUEST FTDI_SIO_RESET |
| #define FTDI_SIO_RESET_REQUEST_TYPE 0x40 |
| #define FTDI_SIO_RESET_SIO 0 |
| #define FTDI_SIO_RESET_PURGE_RX 1 |
| #define FTDI_SIO_RESET_PURGE_TX 2 |
| |
| /* |
| * BmRequestType: 0100 0000B |
| * bRequest: FTDI_SIO_RESET |
| * wValue: Control Value |
| * 0 = Reset SIO |
| * 1 = Purge RX buffer |
| * 2 = Purge TX buffer |
| * wIndex: Port |
| * wLength: 0 |
| * Data: None |
| * |
| * The Reset SIO command has this effect: |
| * |
| * Sets flow control set to 'none' |
| * Event char = $0D |
| * Event trigger = disabled |
| * Purge RX buffer |
| * Purge TX buffer |
| * Clear DTR |
| * Clear RTS |
| * baud and data format not reset |
| * |
| * The Purge RX and TX buffer commands affect nothing except the buffers |
| * |
| */ |
| |
| /* FTDI_SIO_SET_BAUDRATE */ |
| #define FTDI_SIO_SET_BAUDRATE_REQUEST_TYPE 0x40 |
| #define FTDI_SIO_SET_BAUDRATE_REQUEST 3 |
| |
| /* |
| * BmRequestType: 0100 0000B |
| * bRequest: FTDI_SIO_SET_BAUDRATE |
| * wValue: BaudDivisor value - see below |
| * wIndex: Port |
| * wLength: 0 |
| * Data: None |
| * The BaudDivisor values are calculated as follows: |
| * - BaseClock is either 12000000 or 48000000 depending on the device. |
| * FIXME: I wish I knew how to detect old chips to select proper base clock! |
| * - BaudDivisor is a fixed point number encoded in a funny way. |
| * (--WRONG WAY OF THINKING--) |
| * BaudDivisor is a fixed point number encoded with following bit weighs: |
| * (-2)(-1)(13..0). It is a radical with a denominator of 4, so values |
| * end with 0.0 (00...), 0.25 (10...), 0.5 (01...), and 0.75 (11...). |
| * (--THE REALITY--) |
| * The both-bits-set has quite different meaning from 0.75 - the chip |
| * designers have decided it to mean 0.125 instead of 0.75. |
| * This info looked up in FTDI application note "FT8U232 DEVICES \ Data Rates |
| * and Flow Control Consideration for USB to RS232". |
| * - BaudDivisor = (BaseClock / 16) / BaudRate, where the (=) operation should |
| * automagically re-encode the resulting value to take fractions into |
| * consideration. |
| * As all values are integers, some bit twiddling is in order: |
| * BaudDivisor = (BaseClock / 16 / BaudRate) | |
| * (((BaseClock / 2 / BaudRate) & 4) ? 0x4000 // 0.5 |
| * : ((BaseClock / 2 / BaudRate) & 2) ? 0x8000 // 0.25 |
| * : ((BaseClock / 2 / BaudRate) & 1) ? 0xc000 // 0.125 |
| * : 0) |
| * |
| * For the FT232BM, a 17th divisor bit was introduced to encode the multiples |
| * of 0.125 missing from the FT8U232AM. Bits 16 to 14 are coded as follows |
| * (the first four codes are the same as for the FT8U232AM, where bit 16 is |
| * always 0): |
| * 000 - add .000 to divisor |
| * 001 - add .500 to divisor |
| * 010 - add .250 to divisor |
| * 011 - add .125 to divisor |
| * 100 - add .375 to divisor |
| * 101 - add .625 to divisor |
| * 110 - add .750 to divisor |
| * 111 - add .875 to divisor |
| * Bits 15 to 0 of the 17-bit divisor are placed in the urb value. Bit 16 is |
| * placed in bit 0 of the urb index. |
| * |
| * Note that there are a couple of special cases to support the highest baud |
| * rates. If the calculated divisor value is 1, this needs to be replaced with |
| * 0. Additionally for the FT232BM, if the calculated divisor value is 0x4001 |
| * (1.5), this needs to be replaced with 0x0001 (1) (but this divisor value is |
| * not supported by the FT8U232AM). |
| */ |
| |
| enum ftdi_sio_baudrate { |
| ftdi_sio_b300 = 0, |
| ftdi_sio_b600 = 1, |
| ftdi_sio_b1200 = 2, |
| ftdi_sio_b2400 = 3, |
| ftdi_sio_b4800 = 4, |
| ftdi_sio_b9600 = 5, |
| ftdi_sio_b19200 = 6, |
| ftdi_sio_b38400 = 7, |
| ftdi_sio_b57600 = 8, |
| ftdi_sio_b115200 = 9 |
| }; |
| |
| /* |
| * The ftdi_8U232AM_xxMHz_byyy constants have been removed. The encoded divisor |
| * values are calculated internally. |
| */ |
| #define FTDI_SIO_SET_DATA_REQUEST FTDI_SIO_SET_DATA |
| #define FTDI_SIO_SET_DATA_REQUEST_TYPE 0x40 |
| #define FTDI_SIO_SET_DATA_PARITY_NONE (0x0 << 8) |
| #define FTDI_SIO_SET_DATA_PARITY_ODD (0x1 << 8) |
| #define FTDI_SIO_SET_DATA_PARITY_EVEN (0x2 << 8) |
| #define FTDI_SIO_SET_DATA_PARITY_MARK (0x3 << 8) |
| #define FTDI_SIO_SET_DATA_PARITY_SPACE (0x4 << 8) |
| #define FTDI_SIO_SET_DATA_STOP_BITS_1 (0x0 << 11) |
| #define FTDI_SIO_SET_DATA_STOP_BITS_15 (0x1 << 11) |
| #define FTDI_SIO_SET_DATA_STOP_BITS_2 (0x2 << 11) |
| #define FTDI_SIO_SET_BREAK (0x1 << 14) |
| /* FTDI_SIO_SET_DATA */ |
| |
| /* |
| * BmRequestType: 0100 0000B |
| * bRequest: FTDI_SIO_SET_DATA |
| * wValue: Data characteristics (see below) |
| * wIndex: Port |
| * wLength: 0 |
| * Data: No |
| * |
| * Data characteristics |
| * |
| * B0..7 Number of data bits |
| * B8..10 Parity |
| * 0 = None |
| * 1 = Odd |
| * 2 = Even |
| * 3 = Mark |
| * 4 = Space |
| * B11..13 Stop Bits |
| * 0 = 1 |
| * 1 = 1.5 |
| * 2 = 2 |
| * B14 |
| * 1 = TX ON (break) |
| * 0 = TX OFF (normal state) |
| * B15 Reserved |
| * |
| */ |
| |
| |
| |
| /* FTDI_SIO_MODEM_CTRL */ |
| #define FTDI_SIO_SET_MODEM_CTRL_REQUEST_TYPE 0x40 |
| #define FTDI_SIO_SET_MODEM_CTRL_REQUEST FTDI_SIO_MODEM_CTRL |
| |
| /* |
| * BmRequestType: 0100 0000B |
| * bRequest: FTDI_SIO_MODEM_CTRL |
| * wValue: ControlValue (see below) |
| * wIndex: Port |
| * wLength: 0 |
| * Data: None |
| * |
| * NOTE: If the device is in RTS/CTS flow control, the RTS set by this |
| * command will be IGNORED without an error being returned |
| * Also - you can not set DTR and RTS with one control message |
| */ |
| |
| #define FTDI_SIO_SET_DTR_MASK 0x1 |
| #define FTDI_SIO_SET_DTR_HIGH ((FTDI_SIO_SET_DTR_MASK << 8) | 1) |
| #define FTDI_SIO_SET_DTR_LOW ((FTDI_SIO_SET_DTR_MASK << 8) | 0) |
| #define FTDI_SIO_SET_RTS_MASK 0x2 |
| #define FTDI_SIO_SET_RTS_HIGH ((FTDI_SIO_SET_RTS_MASK << 8) | 2) |
| #define FTDI_SIO_SET_RTS_LOW ((FTDI_SIO_SET_RTS_MASK << 8) | 0) |
| |
| /* |
| * ControlValue |
| * B0 DTR state |
| * 0 = reset |
| * 1 = set |
| * B1 RTS state |
| * 0 = reset |
| * 1 = set |
| * B2..7 Reserved |
| * B8 DTR state enable |
| * 0 = ignore |
| * 1 = use DTR state |
| * B9 RTS state enable |
| * 0 = ignore |
| * 1 = use RTS state |
| * B10..15 Reserved |
| */ |
| |
| /* FTDI_SIO_SET_FLOW_CTRL */ |
| #define FTDI_SIO_SET_FLOW_CTRL_REQUEST_TYPE 0x40 |
| #define FTDI_SIO_SET_FLOW_CTRL_REQUEST FTDI_SIO_SET_FLOW_CTRL |
| #define FTDI_SIO_DISABLE_FLOW_CTRL 0x0 |
| #define FTDI_SIO_RTS_CTS_HS (0x1 << 8) |
| #define FTDI_SIO_DTR_DSR_HS (0x2 << 8) |
| #define FTDI_SIO_XON_XOFF_HS (0x4 << 8) |
| /* |
| * BmRequestType: 0100 0000b |
| * bRequest: FTDI_SIO_SET_FLOW_CTRL |
| * wValue: Xoff/Xon |
| * wIndex: Protocol/Port - hIndex is protocol / lIndex is port |
| * wLength: 0 |
| * Data: None |
| * |
| * hIndex protocol is: |
| * B0 Output handshaking using RTS/CTS |
| * 0 = disabled |
| * 1 = enabled |
| * B1 Output handshaking using DTR/DSR |
| * 0 = disabled |
| * 1 = enabled |
| * B2 Xon/Xoff handshaking |
| * 0 = disabled |
| * 1 = enabled |
| * |
| * A value of zero in the hIndex field disables handshaking |
| * |
| * If Xon/Xoff handshaking is specified, the hValue field should contain the |
| * XOFF character and the lValue field contains the XON character. |
| */ |
| |
| /* |
| * FTDI_SIO_GET_LATENCY_TIMER |
| * |
| * Set the timeout interval. The FTDI collects data from the |
| * device, transmitting it to the host when either A) 62 bytes are |
| * received, or B) the timeout interval has elapsed and the buffer |
| * contains at least 1 byte. Setting this value to a small number |
| * can dramatically improve performance for applications which send |
| * small packets, since the default value is 16ms. |
| */ |
| #define FTDI_SIO_GET_LATENCY_TIMER_REQUEST FTDI_SIO_GET_LATENCY_TIMER |
| #define FTDI_SIO_GET_LATENCY_TIMER_REQUEST_TYPE 0xC0 |
| |
| /* |
| * BmRequestType: 1100 0000b |
| * bRequest: FTDI_SIO_GET_LATENCY_TIMER |
| * wValue: 0 |
| * wIndex: Port |
| * wLength: 0 |
| * Data: latency (on return) |
| */ |
| |
| /* |
| * FTDI_SIO_SET_LATENCY_TIMER |
| * |
| * Set the timeout interval. The FTDI collects data from the |
| * device, transmitting it to the host when either A) 62 bytes are |
| * received, or B) the timeout interval has elapsed and the buffer |
| * contains at least 1 byte. Setting this value to a small number |
| * can dramatically improve performance for applications which send |
| * small packets, since the default value is 16ms. |
| */ |
| #define FTDI_SIO_SET_LATENCY_TIMER_REQUEST FTDI_SIO_SET_LATENCY_TIMER |
| #define FTDI_SIO_SET_LATENCY_TIMER_REQUEST_TYPE 0x40 |
| |
| /* |
| * BmRequestType: 0100 0000b |
| * bRequest: FTDI_SIO_SET_LATENCY_TIMER |
| * wValue: Latency (milliseconds) |
| * wIndex: Port |
| * wLength: 0 |
| * Data: None |
| * |
| * wValue: |
| * B0..7 Latency timer |
| * B8..15 0 |
| * |
| */ |
| |
| /* |
| * FTDI_SIO_SET_EVENT_CHAR |
| * |
| * Set the special event character for the specified communications port. |
| * If the device sees this character it will immediately return the |
| * data read so far - rather than wait 40ms or until 62 bytes are read |
| * which is what normally happens. |
| */ |
| |
| |
| #define FTDI_SIO_SET_EVENT_CHAR_REQUEST FTDI_SIO_SET_EVENT_CHAR |
| #define FTDI_SIO_SET_EVENT_CHAR_REQUEST_TYPE 0x40 |
| |
| |
| /* |
| * BmRequestType: 0100 0000b |
| * bRequest: FTDI_SIO_SET_EVENT_CHAR |
| * wValue: EventChar |
| * wIndex: Port |
| * wLength: 0 |
| * Data: None |
| * |
| * wValue: |
| * B0..7 Event Character |
| * B8 Event Character Processing |
| * 0 = disabled |
| * 1 = enabled |
| * B9..15 Reserved |
| * |
| */ |
| |
| /* FTDI_SIO_SET_ERROR_CHAR */ |
| |
| /* |
| * Set the parity error replacement character for the specified communications |
| * port |
| */ |
| |
| /* |
| * BmRequestType: 0100 0000b |
| * bRequest: FTDI_SIO_SET_EVENT_CHAR |
| * wValue: Error Char |
| * wIndex: Port |
| * wLength: 0 |
| * Data: None |
| * |
| *Error Char |
| * B0..7 Error Character |
| * B8 Error Character Processing |
| * 0 = disabled |
| * 1 = enabled |
| * B9..15 Reserved |
| * |
| */ |
| |
| /* FTDI_SIO_GET_MODEM_STATUS */ |
| /* Retrieve the current value of the modem status register */ |
| |
| #define FTDI_SIO_GET_MODEM_STATUS_REQUEST_TYPE 0xc0 |
| #define FTDI_SIO_GET_MODEM_STATUS_REQUEST FTDI_SIO_GET_MODEM_STATUS |
| #define FTDI_SIO_CTS_MASK 0x10 |
| #define FTDI_SIO_DSR_MASK 0x20 |
| #define FTDI_SIO_RI_MASK 0x40 |
| #define FTDI_SIO_RLSD_MASK 0x80 |
| /* |
| * BmRequestType: 1100 0000b |
| * bRequest: FTDI_SIO_GET_MODEM_STATUS |
| * wValue: zero |
| * wIndex: Port |
| * wLength: 1 |
| * Data: Status |
| * |
| * One byte of data is returned |
| * B0..3 0 |
| * B4 CTS |
| * 0 = inactive |
| * 1 = active |
| * B5 DSR |
| * 0 = inactive |
| * 1 = active |
| * B6 Ring Indicator (RI) |
| * 0 = inactive |
| * 1 = active |
| * B7 Receive Line Signal Detect (RLSD) |
| * 0 = inactive |
| * 1 = active |
| */ |
| |
| /* FTDI_SIO_SET_BITMODE */ |
| #define FTDI_SIO_SET_BITMODE_REQUEST_TYPE 0x40 |
| #define FTDI_SIO_SET_BITMODE_REQUEST FTDI_SIO_SET_BITMODE |
| |
| /* Possible bitmodes for FTDI_SIO_SET_BITMODE_REQUEST */ |
| #define FTDI_SIO_BITMODE_RESET 0x00 |
| #define FTDI_SIO_BITMODE_CBUS 0x20 |
| |
| /* FTDI_SIO_READ_PINS */ |
| #define FTDI_SIO_READ_PINS_REQUEST_TYPE 0xc0 |
| #define FTDI_SIO_READ_PINS_REQUEST FTDI_SIO_READ_PINS |
| |
| /* |
| * FTDI_SIO_READ_EEPROM |
| * |
| * EEPROM format found in FTDI AN_201, "FT-X MTP memory Configuration", |
| * http://www.ftdichip.com/Support/Documents/AppNotes/AN_201_FT-X%20MTP%20Memory%20Configuration.pdf |
| */ |
| #define FTDI_SIO_READ_EEPROM_REQUEST_TYPE 0xc0 |
| #define FTDI_SIO_READ_EEPROM_REQUEST FTDI_SIO_READ_EEPROM |
| |
| #define FTDI_FTX_CBUS_MUX_GPIO 0x8 |
| #define FTDI_FT232R_CBUS_MUX_GPIO 0xa |
| |
| |
| /* Descriptors returned by the device |
| * |
| * Device Descriptor |
| * |
| * Offset Field Size Value Description |
| * 0 bLength 1 0x12 Size of descriptor in bytes |
| * 1 bDescriptorType 1 0x01 DEVICE Descriptor Type |
| * 2 bcdUSB 2 0x0110 USB Spec Release Number |
| * 4 bDeviceClass 1 0x00 Class Code |
| * 5 bDeviceSubClass 1 0x00 SubClass Code |
| * 6 bDeviceProtocol 1 0x00 Protocol Code |
| * 7 bMaxPacketSize0 1 0x08 Maximum packet size for endpoint 0 |
| * 8 idVendor 2 0x0403 Vendor ID |
| * 10 idProduct 2 0x8372 Product ID (FTDI_SIO_PID) |
| * 12 bcdDevice 2 0x0001 Device release number |
| * 14 iManufacturer 1 0x01 Index of man. string desc |
| * 15 iProduct 1 0x02 Index of prod string desc |
| * 16 iSerialNumber 1 0x02 Index of serial nmr string desc |
| * 17 bNumConfigurations 1 0x01 Number of possible configurations |
| * |
| * Configuration Descriptor |
| * |
| * Offset Field Size Value |
| * 0 bLength 1 0x09 Size of descriptor in bytes |
| * 1 bDescriptorType 1 0x02 CONFIGURATION Descriptor Type |
| * 2 wTotalLength 2 0x0020 Total length of data |
| * 4 bNumInterfaces 1 0x01 Number of interfaces supported |
| * 5 bConfigurationValue 1 0x01 Argument for SetCOnfiguration() req |
| * 6 iConfiguration 1 0x02 Index of config string descriptor |
| * 7 bmAttributes 1 0x20 Config characteristics Remote Wakeup |
| * 8 MaxPower 1 0x1E Max power consumption |
| * |
| * Interface Descriptor |
| * |
| * Offset Field Size Value |
| * 0 bLength 1 0x09 Size of descriptor in bytes |
| * 1 bDescriptorType 1 0x04 INTERFACE Descriptor Type |
| * 2 bInterfaceNumber 1 0x00 Number of interface |
| * 3 bAlternateSetting 1 0x00 Value used to select alternate |
| * 4 bNumEndpoints 1 0x02 Number of endpoints |
| * 5 bInterfaceClass 1 0xFF Class Code |
| * 6 bInterfaceSubClass 1 0xFF Subclass Code |
| * 7 bInterfaceProtocol 1 0xFF Protocol Code |
| * 8 iInterface 1 0x02 Index of interface string description |
| * |
| * IN Endpoint Descriptor |
| * |
| * Offset Field Size Value |
| * 0 bLength 1 0x07 Size of descriptor in bytes |
| * 1 bDescriptorType 1 0x05 ENDPOINT descriptor type |
| * 2 bEndpointAddress 1 0x82 Address of endpoint |
| * 3 bmAttributes 1 0x02 Endpoint attributes - Bulk |
| * 4 bNumEndpoints 2 0x0040 maximum packet size |
| * 5 bInterval 1 0x00 Interval for polling endpoint |
| * |
| * OUT Endpoint Descriptor |
| * |
| * Offset Field Size Value |
| * 0 bLength 1 0x07 Size of descriptor in bytes |
| * 1 bDescriptorType 1 0x05 ENDPOINT descriptor type |
| * 2 bEndpointAddress 1 0x02 Address of endpoint |
| * 3 bmAttributes 1 0x02 Endpoint attributes - Bulk |
| * 4 bNumEndpoints 2 0x0040 maximum packet size |
| * 5 bInterval 1 0x00 Interval for polling endpoint |
| * |
| * 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 |
| * |
| * Offset Description |
| * B0 Reserved - must be 1 |
| * B1 Reserved - must be 0 |
| * B2 Reserved - must be 0 |
| * B3 Reserved - must be 0 |
| * B4 Clear to Send (CTS) |
| * B5 Data Set Ready (DSR) |
| * B6 Ring Indicator (RI) |
| * B7 Receive Line Signal Detect (RLSD) |
| * |
| * Byte 1: Line Status |
| * |
| * 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 |
| * |
| */ |
| #define FTDI_RS0_CTS (1 << 4) |
| #define FTDI_RS0_DSR (1 << 5) |
| #define FTDI_RS0_RI (1 << 6) |
| #define FTDI_RS0_RLSD (1 << 7) |
| |
| #define FTDI_RS_DR 1 |
| #define FTDI_RS_OE (1<<1) |
| #define FTDI_RS_PE (1<<2) |
| #define FTDI_RS_FE (1<<3) |
| #define FTDI_RS_BI (1<<4) |
| #define FTDI_RS_THRE (1<<5) |
| #define FTDI_RS_TEMT (1<<6) |
| #define FTDI_RS_FIFO (1<<7) |
| |
| /* |
| * 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: Line Status |
| * |
| * Offset Description |
| * B0 Reserved - must be 1 |
| * B1 Reserved - must be 0 |
| * B2..7 Length of message - (not including Byte 0) |
| * |
| */ |
