The following list is of FTDI-specific commands sent via the ioctl system call to the USB driver. The usb_control_msg routine of libusb wraps these commands into the correct ioctl format. The 7 parameters of the usb_control_msg are:
struct usb_device The particular USB device to talk with 1-byte request type Read (0xC0), Write(0x40), or read and write 1-byte command Defined by FTDI firmware 2-byte Value Defined by FTDI firmware 2-byte Index Defined by FTDI firmware pointer to data structure Defined by FTDI firmware 2-byte size of data structure sizeof(data structure) Timeout read or write Timeout (5000 milliseconds is typical)
These are the command messages issued by libftdi routines:
reset: usb_control_msg(ftdi->usb_dev, 0x40, 0x00, 0, Index, NULL, 0, Timeout)
purge RX buffer: usb_control_msg(ftdi->usb_dev, 0x40, 0x00, 1, Index, NULL, 0, Timeout)
purge TX buffer: usb_control_msg(ftdi->usb_dev, 0x40, 0x00, 2, Index, NULL, 0, Timeout)
setflowctrl: usb_control_msg(ftdi->usb_dev, 0x40, 0x01, Value, Index, NULL, 0, Timeout)
Value encodes cc parameters, etc. (See ftdi_sio.c in Linux Kernel for details.)
Index encodes the following flow control options:
0x00 Disable flow control on Channel A
0x01 Disable flow control on Channel B
0x10 Set RTS/CTS flow control on Channel A
0x11 Set RTS/CTS flow control on Channel B
0x20 Set DTR/DSR flow control on Channel A
0x21 Set DTR/DSR flow control on Channel B
0x40 Set XON/XOFF flow control on Channel A
0x41 Set XON/XOFF flow control on Channel B
set DTR: usb_control_msg(ftdi->usb_dev, 0x40, 0x02, Value, Interface, NULL, 0, Timeout)
Value is 0x10 to set DTR Low, 0x11 to set DTR High
Interface is 0 for Channel A, 1 for Channel B
set RTS: usb_control_msg(ftdi->usb_dev, 0x40, 0x02, Value, Interface, NULL, 0, Timeout)
Value is 0x20 to set RTS Low, 0x21 to set RTS High
Interface is 0 for Channel A, 1 for Channel B
set baudrate: usb_control_msg(ftdi->usb_dev, 0x40, 0x03, Value, Index, NULL, 0, Timeout)
Value and Index combined encode the divisor and output channel.
(See ftdi_convert_baudrate for details.)
set line property: usb_control_msg(ftdi->usb_dev, 0x40, 0x04, Value, Interface, NULL, 0, Timeout)
Value encodes the number of data bits, stop bits and parity.
Bits 0-7: Number of data bits
Bits 8-10: Parity: NONE=0x00, ODD=0x01, EVEN=0x02, MARK=0x03, SPACE=0x04
Bits 11-12: Stop bits: STOP_BIT_1=0x00, STOP_BIT_15=0x01, STOP_BIT_2=0x02
Interface is 0 for Channel A, 1 for Channel B
get modem status: usb_control_msg(ftdi->usb_dev, 0xC0, 0x05, Value, Interface, (char *)&Value, 0, Timeout)
Value is returned with the following bits set:
Bit 4: CTS state
Bit 5: DSR state
Bit 6: RI state
Bit 7: RLSD state
Interface is 0 for Channel A, 1 for Channel B
set event char: usb_control_msg(ftdi->usb_dev, 0x40, 0x06, Value, Interface, NULL, 0, Timeout)
Value encodes the event character and whether it is to be used:
Bits 0-7: Event character
Bit 8: Event character enabled=1, disabled=0
Interface is 0 for Channel A, 1 for Channel B
set error char: usb_control_msg(ftdi->usb_dev, 0x40, 0x07, Value, Interface, NULL, 0, Timeout)
Value encodes the error character and whether it is to be used:
Bits 0-7: Error character
Bit 8: Error character enabled=1, disabled=0
set latency time: usb_control_msg(ftdi->usb_dev, 0x40, 0x09, Value, Interface, NULL, 0, Timeout)
Value has the latency time with Value between 1 and 255 milliseconds.)
Interface is 0 for Channel A, 1 for Channel B
get latency time: usb_control_msg(ftdi->usb_dev, 0xC0, 0x0A, 0, Interface, (char *)&Value, 1, Timeout)
The current latency time will be placed in Value.
Interface is 0 for Channel A, 1 for Channel B
enable bitbang: usb_control_msg(ftdi->usb_dev, 0x40, 0x0B, Value, Index, NULL, 0, Timeout)
Value encodes the bitmask and bitbang mode (1=normal, 2=SPI bitbang mode).
Index encodes channel (1 = Channel A, 2 = Channel B)
disable bitbang: usb_control_msg(ftdi->usb_dev, 0x40, 0x0B, 0, Index, NULL, 0, Timeout)
Index encodes channel (1 = Channel A, 2 = Channel B)
set bitmode: usb_control_msg(ftdi->usb_dev, 0x40, 0x0B, Value, Index, NULL, 0, Timeout)
Value encodes the bitmask in bits 0-7 and MPSSE bitmode in bits 8-12.
The bitmode bits are:
0x00 Reset I/O Bit Mode
0x01 Asynchronous Bit Bang Mode
0x02 Multi-Protocol Synchronous Serial Engine Mode
0x04 Synchronous Bit Bang Mode
0x08 MCU Host Bus Emulation Mode
0x10 Fast Opto-Isolated Serial Interface Mode
Index encodes channel (1 = Channel A, 2 = Channel B)
read pins: usb_control_msg(ftdi->usb_dev, 0xC0, 0x0C, 0, Index, (char *)&Value, 1, Timeout)
Index encodes channel (1 = Channel A, 2 = Channel B)
The bits of Value will contain the pin settings.
read eeprom: usb_control_msg(ftdi->usb_dev, 0xC0, 0x90, 0, i, eeprom+(i*2), 2, Timeout)
Called for each byte pair read from EEPROM. Results put in the 128-byte eeprom string.
write eeprom: usb_control_msg(ftdi->usb_dev, 0x40, 0x91, Value, i, NULL, 0, Timeout)
Called for each byte pair to be written to EEPROM address i.
Value contains the pair of bytes starting at EEPROM address i.
erase eeprom: usb_control_msg(ftdi->usb_dev, 0x40, 0x92, 0, 0, NULL, 0, Timeout)
Last updated: February 19, 2007