- Datasheets
- Accessories
- CB15
- CB25
- CB37 V1.2
- CB37 V2.1
- EB37
- EI-1022
- EI-1034
- EI-1040
- EI-1050
- IDCA-10
- LJTick-CurrentShunt
- LJTick-DAC
- LJTick-DAC Testing Utility
- LJTick-DigitalOut5V
- LJTick-Divider
- LJTick-InAmp
- LJTick-InBuff
- LJTick-LVDigitalIO
- LJTick-OutBuff
- LJTick-Proto
- LJTick-RelayDriver
- LJTick-Resistance
- LJTick-VRef
- Mux80 AIN Expansion Board
- PS12DC
- RB12
- RB16
- T-Series Datasheet
- Preface: Warranty, Liability, Compliance
- 1.0 Device Overview
- 2.0 Installation
- 3.0 Communication
- 4.0 Hardware Overview
- 5.0 USB
- 6.0 Ethernet
- 7.0 WiFi (T7-Pro only)
- 8.0 LEDs
- 9.0 VS, Power Supply
- 10.0 SGND and GND
- 11.0 SPC
- 12.0 200uA and 10uA (T7 Only)
- 13.0 Digital I/O
- 13.1 Flexible I/O (T4 Only)
- 13.2 DIO Extended Features
- 13.2.1 EF Clock Source
- 13.2.2 PWM Out
- 13.2.3 PWM Out with Phase
- 13.2.4 Pulse Out
- 13.2.5 Frequency In
- 13.2.6 Pulse Width In
- 13.2.7 Line-to-Line In
- 13.2.8 High-Speed Counter
- 13.2.9 Interrupt Counter
- 13.2.10 Interrupt Counter with Debounce
- 13.2.11 Quadrature In
- 13.2.12 Interrupt Frequency In
- 13.2.13 Conditional Reset
- 13.3 I2C
- 13.4 SPI
- 13.5 SBUS
- 13.6 1-Wire
- 13.7 Asynchronous Serial
- 14.0 Analog Inputs
- 15.0 DAC
- 16.0 DB37 (T7 Only)
- 17.0 DB15
- 18.0 Internal Temp Sensor
- 19.0 RTC (T7 Only)
- 20.0 Internal Flash
- 21.0 SD Card (T7 Only)
- 22.0 OEM Versions
- 23.0 Watchdog
- 24.0 IO Config, _DEFAULT
- 25.0 Lua Scripting
- Appendix A - Specifications
- Appendix B - Drawings and CAD Models
- Appendix C - Firmware Revision History
- Appendix D - Packaging Information
- Appendix E - Software Options
- U3 Datasheet
- Preface
- 1 - Installation
- 2 - Hardware Description
- 2.1 - USB
- 2.2 - Status LED
- 2.3 - GND and SGND
- 2.4 - VS
- 2.5 - Flexible I/O (FIO/EIO)
- 2.6 - AIN
- 2.6.1 - Channel Numbers
- 2.6.2 - Converting Binary Readings to Voltages
- 2.6.3 - Typical Analog Input Connections
- 2.6.3.1 - Signal from the LabJack
- 2.6.3.2 - Unpowered Isolated Signal
- 2.6.3.3 - Signal Powered By the LabJack
- 2.6.3.4 - Signal Powered Externally
- 2.6.3.5 - Amplifying Small Signal Voltages
- 2.6.3.6 - Signal Voltages Beyond 0-2.44 Volts (and Resistance Measurement)
- 2.6.3.7 - Measuring Current (Including 4-20 mA) with a Resistive Shunt
- 2.6.3.8 - Floating/Unconnected Inputs
- 2.6.3.9 - Signal Voltages Near Ground
- 2.6.4 - Internal Temperature Sensor
- 2.7 - DAC
- 2.8 - Digital I/O
- 2.9 - Timers/Counters
- 2.9.1 - Timer Mode Descriptions
- 2.9.1.1 - PWM Output (16-Bit, Mode 0)
- 2.9.1.2 - PWM Output (8-Bit, Mode 1)
- 2.9.1.3 - Period Measurement (32-Bit, Modes 2 & 3)
- 2.9.1.4 - Duty Cycle Measurement (Mode 4)
- 2.9.1.5 - Firmware Counter Input (Mode 5)
- 2.9.1.6 - Firmware Counter Input With Debounce (Mode 6)
- 2.9.1.7 - Frequency Output (Mode 7)
- 2.9.1.8 - Quadrature Input (Mode 8)
- 2.9.1.9 - Timer Stop Input (Mode 9)
- 2.9.1.10 - System Timer Low/High Read (Modes 10 & 11)
- 2.9.1.11 - Period Measurement (16-Bit, Modes 12 & 13)
- 2.9.1.12 - Line-to-Line Measurement (Mode 14)
- 2.9.2 - Timer Operation/Performance Notes
- 2.9.1 - Timer Mode Descriptions
- 2.10 - SPC (… and SCL/SDA/SCA)
- 2.11 - DB15
- 2.12 - U3-OEM
- 2.13 - Hardware Revision Notes
- 3 - Operation
- 4 - LabJackUD High-Level Driver
- 4.1 - Overview
- 4.2 - Function Reference
- 4.2.1 - ListAll()
- 4.2.2 - OpenLabJack()
- 4.2.3 - eGet() and ePut()
- 4.2.4 - eAddGoGet()
- 4.2.5 - AddRequest()
- 4.2.6 - Go()
- 4.2.7 - GoOne()
- 4.2.8 - GetResult()
- 4.2.9 - GetFirstResult() and GetNextResult()
- 4.2.10 - DoubleToStringAddress()
- 4.2.11 - StringToDoubleAddress()
- 4.2.12 - StringToConstant()
- 4.2.13 - ErrorToString()
- 4.2.14 - GetDriverVersion()
- 4.2.15 - TCVoltsToTemp()
- 4.2.16 - ResetLabJack()
- 4.2.17 - eAIN()
- 4.2.18 - eDAC()
- 4.2.19 - eDI()
- 4.2.20 - eDO()
- 4.2.21 - eTCConfig()
- 4.2.22 - eTCValues()
- 4.3 - Example Pseudocode
- 4.3.1 - Open
- 4.3.2 - Configuration
- 4.3.3 - Analog Inputs
- 4.3.4 - Analog Outputs
- 4.3.5 - Digital I/O
- 4.3.6 - Timers & Counters
- 4.3.7 - Stream Mode
- 4.3.8 - Raw Output/Input
- 4.3.9 - Easy Functions
- 4.3.10 - SPI Serial Communication
- 4.3.11 - I²C Serial Communication
- 4.3.12 - Asynchronous Serial Communication
- 4.3.13 - Watchdog Timer
- 4.3.14 - Miscellaneous
- 4.4 - Errorcodes
- 5 - Low-level Function Reference
- 5.1 - General Protocol
- 5.2 - Low-Level Functions
- 5.2.1 - Bad Checksum
- 5.2.2 - ConfigU3
- 5.2.3 - ConfigIO
- 5.2.4 - ConfigTimerClock
- 5.2.5 - Feedback
- 5.2.5.1 - AIN: IOType = 1
- 5.2.5.2 - WaitShort: IOType=5
- 5.2.5.3 - WaitLong: IOType=6
- 5.2.5.4 - LED: IOType=9
- 5.2.5.5 - BitStateRead: IOType=10
- 5.2.5.6 - BitStateWrite: IOType=11
- 5.2.5.7 - BitDirRead: IOType=12
- 5.2.5.8 - BitDirWrite: IOType=13
- 5.2.5.9 - PortStateRead: IOType=26
- 5.2.5.10 - PortStateWrite: IOType=27
- 5.2.5.11 - PortDirRead: IOType=28
- 5.2.5.12 - PortDirWrite: IOType=29
- 5.2.5.13 - DAC# (8-bit): IOType=34,35
- 5.2.5.14 - DAC# (16-bit): IOType=38,39
- 5.2.5.15 - Timer#: IOType=42,44
- 5.2.5.16 - Timer#Config: IOType=43,45
- 5.2.5.17 - Counter#: IOType=54,55
- 5.2.5.18 - Buzzer: IOType=63
- 5.2.6 - ReadMem (ReadCal)
- 5.2.7 - WriteMem (WriteCal)
- 5.2.8 - EraseMem (EraseCal)
- 5.2.9 - Reset
- 5.2.10 - StreamConfig
- 5.2.11 - StreamStart
- 5.2.12 - StreamData
- 5.2.13 - StreamStop
- 5.2.14 - Watchdog
- 5.2.15 - SPI
- 5.2.16 - AsynchConfig
- 5.2.17 - AsynchTX
- 5.2.18 - AsynchRX
- 5.2.19 - I²C
- 5.2.20 - SHT1X
- 5.2.21 - SetDefaults (SetToFactoryDefaults)
- 5.2.22 - ReadDefaults (ReadCurrent)
- 5.2.23 - 1-Wire
- 5.3 - Errorcodes
- 5.4 - Calibration Constants
- Appendix A - Specifications
- Appendix B - Enclosure and PCB Drawings
- U3 Firmware Revision History
- U6 Datasheet
- Preface: Warranty, Liability, Compliance
- 1 - Installation
- 2 - Hardware Description
- 2.1 - USB
- 2.2 - Power and Status LED
- 2.3 - GND and SGND
- 2.4 - VS
- 2.5 - 10UA and 200UA
- 2.6 - AIN
- 2.6.1 - Channel Numbers
- 2.6.2 - Converting Binary Readings to Voltages
- 2.6.3 - Typical Analog Input Connections
- 2.6.3.1 - Signal from the LabJack
- 2.6.3.2 - Unpowered Isolated Signal
- 2.6.3.3 - Signal Powered By the LabJack
- 2.6.3.4 - Signal Powered Externally
- 2.6.3.5 - Amplifying Small Signal Voltages
- 2.6.3.6 - Signal Voltages Beyond ±10 Volts (and Resistance Measurement)
- 2.6.3.7 - Measuring Current (Including 4-20 mA) with a Resistive Shunt
- 2.6.3.8 - Floating/Unconnected Inputs
- 2.6.4 - Internal Temperature Sensor
- 2.6.5 - Signal Range
- 2.7 - DAC
- 2.8 - Digital I/O
- 2.9 - Timers/Counters
- 2.9.1 - Timer Mode Descriptions
- 2.9.1.1 - PWM Output (16-Bit, Mode 0)
- 2.9.1.2 - PWM Output (8-Bit, Mode 1)
- 2.9.1.3 - Period Measurement (32-Bit, Modes 2 & 3)
- 2.9.1.4 - Duty Cycle Measurement (Mode 4)
- 2.9.1.5 - Firmware Counter Input (Mode 5)
- 2.9.1.6 - Firmware Counter Input With Debounce (Mode 6)
- 2.9.1.7 - Frequency Output (Mode 7)
- 2.9.1.8 - Quadrature Input (Mode 8)
- 2.9.1.9 - Timer Stop Input (Mode 9)
- 2.9.1.10 - System Timer Low/High Read (Modes 10 & 11)
- 2.9.1.11 - Period Measurement (16-Bit, Modes 12 & 13)
- 2.9.1.12 - Line-to-Line Measurement (Mode 14)
- 2.9.2 - Timer Operation/Performance Notes
- 2.9.1 - Timer Mode Descriptions
- 2.10 - SPC (or VSPC)
- 2.11 - DB37
- 2.12 - DB15
- 2.13 - OEM Connector Options
- 3 - Operation
- 4 - LabJackUD High-Level Driver
- 4.1 - Overview
- 4.2 - Function Reference
- 4.2.1 - ListAll()
- 4.2.2 - OpenLabJack()
- 4.2.3 - eGet() and ePut()
- 4.2.4 - eAddGoGet()
- 4.2.5 - AddRequest()
- 4.2.6 - Go()
- 4.2.7 - GoOne()
- 4.2.8 - GetResult()
- 4.2.9 - GetFirstResult() and GetNextResult()
- 4.2.10 - DoubleToStringAddress()
- 4.2.11 - StringToDoubleAddress()
- 4.2.12 - StringToConstant()
- 4.2.13 - ErrorToString()
- 4.2.14 - GetDriverVersion()
- 4.2.15 - TCVoltsToTemp()
- 4.2.16 - ResetLabJack()
- 4.2.17 - eAIN()
- 4.2.18 - eDAC()
- 4.2.19 - eDI()
- 4.2.20 - eDO()
- 4.2.21 - eTCConfig()
- 4.2.22 - eTCValues()
- 4.3 - Example Pseudocode
- 4.3.1 - Open
- 4.3.2 - Configuration
- 4.3.3 - Analog Inputs
- 4.3.4 - Analog Outputs
- 4.3.5 - Digital I/O
- 4.3.6 - Timers & Counters
- 4.3.7 - Stream Mode
- 4.3.8 - Raw Output/Input
- 4.3.9 - Easy Functions
- 4.3.10 - SPI Serial Communication
- 4.3.11 - I²C Serial Communication
- 4.3.12 - Asynchronous Serial Communication
- 4.3.13 - Watchdog Timer
- 4.3.14 - Miscellaneous
- 4.4 - Errorcodes
- 5 - Low-level Function Reference
- 5.1 - General Protocol
- 5.2 - Low-Level Functions
- 5.2.1 - Bad Checksum
- 5.2.2 - ConfigU6
- 5.2.3 - ConfigIO
- 5.2.4 - ConfigTimerClock
- 5.2.5 - Feedback
- 5.2.5.1 - AIN: IOType = 1
- 5.2.5.2 - AIN24: IOType = 2
- 5.2.5.3 - AIN24AR: IOType = 3
- 5.2.5.4 - WaitShort: IOType=5
- 5.2.5.5 - WaitLong: IOType=6
- 5.2.5.6 - LED: IOType=9
- 5.2.5.7 - BitStateRead: IOType=10
- 5.2.5.8 - BitStateWrite: IOType=11
- 5.2.5.9 - BitDirRead: IOType=12
- 5.2.5.10 - BitDirWrite: IOType=13
- 5.2.5.11 - PortStateRead: IOType=26
- 5.2.5.12 - PortStateWrite: IOType=27
- 5.2.5.13 - PortDirRead: IOType=28
- 5.2.5.14 - PortDirWrite: IOType=29
- 5.2.5.15 - DAC# (8-bit): IOType=34,25
- 5.2.5.16 - DAC# (16-bit): IOType=38,39
- 5.2.5.17 - Timer#: IOType=42,44,46,48
- 5.2.5.18 - Timer#Config: IOType = 43, 45, 47, 49
- 5.2.5.19 - Counter#: IOType = 54, 55
- 5.2.6 - ReadMem (ReadCal)
- 5.2.7 - WriteMem (WriteCal)
- 5.2.8 - EraseMem (EraseCal)
- 5.2.9 - SetDefaults (SetToFactoryDefaults)
- 5.2.10 - ReadDefaults (ReadCurrent)
- 5.2.11 - Reset
- 5.2.12 - StreamConfig
- 5.2.13 - StreamStart
- 5.2.14 - StreamData
- 5.2.15 - StreamStop
- 5.2.16 - Watchdog
- 5.2.17 - SPI
- 5.2.18 - AsynchConfig
- 5.2.19 - AsynchTX
- 5.2.20 - AsynchRX
- 5.2.21 - I²C
- 5.2.22 - SHT1X
- 5.2.23 - 1-Wire
- 5.2.24 - StreamAddChannels
- 5.3 - Errorcodes
- 5.4 - Calibration Constants
- Appendix A - Specifications
- Appendix B - Noise and Resolution Tables
- Appendix C - Enclosure and PCB Drawings
- U6 Firmware Revision History
- Digit Datasheet (Discontinued)
- UE9 Datasheet
- Preface
- 1 - Installation
- 2 - Hardware Description
- 2.1 - USB
- 2.2 - Ethernet
- 2.3 - Vext (Screw Terminals and Power Jack)
- 2.4 - Comm and Control LEDs
- 2.5 - GND and SGND
- 2.6 - VS
- 2.7 - AIN
- 2.7.1 - Channel Numbers
- 2.7.2 - Converting Binary Readings to Voltages
- 2.7.3 - Typical Analog Input Connections
- 2.7.3.1 - Signal from the LabJack
- 2.7.3.2 - Unpowered Isolated Signal
- 2.7.3.3 - Signal Powered by the LabJack
- 2.7.3.4 - Signal Powered Externally
- 2.7.3.5 - Amplifying Small Signal Voltages
- 2.7.3.6 - Signal Voltages Beyond ±5 Volts (and Resistance Measurement)
- 2.7.3.7 - Measuring Current (Including 4-20 mA) with a Resistive Shunt
- 2.7.3.8 - Floating/Unconnected Inputs
- 2.7.4 - Internal Temperature Sensor
- 2.8 - DAC
- 2.9 - Digital I/O
- 2.10 - Timers/Counters
- 2.10.1 - Timer Mode Descriptions
- 2.10.1.1 - PWM Output (16-Bit, Mode 0)
- 2.10.1.2 - PWM Output (8-Bit, Mode 1)
- 2.10.1.3 - Period Measurement (32-Bit, Modes 2 & 3)
- 2.10.1.4 - Duty Cycle Measurement (Mode 4)
- 2.10.1.5 - Firmware Counter Input (Mode 5)
- 2.10.1.6 - Firmware Counter Input With Debounce (Mode 6)
- 2.10.1.7 - Frequency Output (Mode 7)
- 2.10.1.8 - Quadrature Input (Mode 8)
- 2.10.1.9 - Timer Stop Input (Mode 9)
- 2.10.1.10 - System Timer Low/High Read (Modes 10 & 11)
- 2.10.1.11 - Period Measurement (16-Bit, Modes 12 & 13)
- 2.10.2 - Timer Operation/Performance Notes
- 2.10.1 - Timer Mode Descriptions
- 2.11 - SCL and SDA (or SCA)
- 2.12 - DB37
- 2.13 - DB15
- 2.14 - OEM Connector Options
- 3 - Operation
- 4 - LabJackUD High-Level Driver
- 4.1 - Overview
- 4.2 - Function Reference
- 4.2.1 - ListAll()
- 4.2.2 - OpenLabJack()
- 4.2.3 - eGet() and ePut()
- 4.2.4 - eAddGoGet()
- 4.2.5 - AddRequest()
- 4.2.6 - Go()
- 4.2.7 - GoOne()
- 4.2.8 - GetResult()
- 4.2.9 - GetFirstResult() and GetNextResult()
- 4.2.10 - DoubleToStringAddress()
- 4.2.11 - StringToDoubleAddress()
- 4.2.12 - StringToConstant()
- 4.2.13 - ErrorToString()
- 4.2.14 - GetDriverVersion()
- 4.2.15 - TCVoltsToTemp()
- 4.2.16 - ResetLabJack()
- 4.2.17 - eAIN()
- 4.2.18 - eDAC()
- 4.2.19 - eDI()
- 4.2.20 - eDO()
- 4.2.21 - eTCConfig()
- 4.2.22 - eTCValues()
- 4.3 - Example Pseudocode
- 4.3.1 - Open
- 4.3.2 - Configuration
- 4.3.3 - Analog Inputs
- 4.3.4 - Analog Outputs
- 4.3.5 - Digital I/O
- 4.3.6 - Timers & Counters
- 4.3.7 - Stream Mode
- 4.3.8 - Raw Output/Input
- 4.3.9 - Easy Functions
- 4.3.10 - SPI Serial Communication
- 4.3.11 - I²C Serial Communication
- 4.3.12 - Asynchronous Serial Communication
- 4.3.13 - Watchdog Timer
- 4.3.14 - Miscellaneous
- 4.4 - Errorcodes
- 5 - Low-level Function Reference
- 5.1 - General Protocol
- 5.2 - Comm Functions
- 5.3 - Control Functions
- 5.3.1 - BadChecksum
- 5.3.2 - ControlConfig
- 5.3.3 - Feedback (and FeedbackAlt)
- 5.3.4 - SingleIO
- 5.3.5 - TimerCounter
- 5.3.6 - StreamConfig
- 5.3.7 - StreamStart
- 5.3.8 - StreamData
- 5.3.9 - StreamStop
- 5.3.10 - ReadMem
- 5.3.11 - WriteMem
- 5.3.12 - EraseMem
- 5.3.13.1 - WatchdogConfig
- 5.3.13.2 - WatchdogRead
- 5.3.13.3 - Extended WatchdogConfig
- 5.3.13.4 - WatchdogClear
- 5.3.15 - Reset
- 5.3.16 - SPI
- 5.3.17 - AsynchConfig
- 5.3.18 - AsynchTX
- 5.3.19 - AsynchRX
- 5.3.20 - I²C
- 5.3.21 - SHT1X
- 5.3.22 - StreamDAC
- 5.3.23 - SetDefaults (SetToFactoryDefaults)
- 5.3.24 - ReadDefaults (ReadCurrent)
- 5.3.25 - 1-Wire
- 5.4 - Low-Level Errorcodes
- 5.5 - Modbus
- 5.6 - Calibration Constants
- 6 - Low-level Native Examples
- Appendix A - Specifications
- Appendix B - Noise and Resolution Tables
- Appendix C - Enclosure and PCB Drawings
- UE9 Firmware Revision History
- U12 Datasheet
- 1 - Installation
- 2 - Hardware Description
- 3 - Example Applications
- 4 - Programming Reference
- 4.1 - EAnalogIn
- 4.2 - EAnalogOut
- 4.3 - ECount
- 4.4 - EDigitalIn
- 4.5 - EDigitalOut
- 4.6 - AISample
- 4.7 - AIBurst
- 4.8 - AIStreamStart
- 4.9 - AIStreamRead
- 4.10 - AIStreamClear
- 4.11 - AOUpdate
- 4.12 - AsynchConfig
- 4.13 - Asynch
- 4.14 - BitsToVolts
- 4.15 - VoltsToBits
- 4.16 - Counter
- 4.17 - DigitalIO
- 4.18 - GetDriverVersion
- 4.19 - GetErrorString
- 4.20 - GetFirmwareVersion
- 4.21 - GetWinVersion
- 4.22 - ListAll
- 4.23 - LocalID
- 4.24 - NoThread
- 4.25 - PulseOut
- 4.26 - PulseOutStart
- 4.27 - PulseOutFinish
- 4.28 - PulseOutCalc
- 4.29 - ReEnum
- 4.30 - Reset (or ResetLJ)
- 4.31 - SHT1X
- 4.32 - SHTComm
- 4.33 - SHTCRC
- 4.34 - Synch
- 4.35 - Watchdog
- 4.36 - ReadMem
- 4.37 - WriteMem
- 4.38 - BuildOptionBits (ActiveX only)
- 4.39 - FourPack (ActiveX only)
- 4.40 - Description of Errorcodes
- 5 - Low-Level Function Reference
- Appendix A - Specifications
- Appendix B - Dimensions
- Appendix C - U12 Hardware Troubleshooting
- Appendix D - Maximum Data Rates for the LabJack U12
- Accessories
5 comments
I had read elsewhere on this
I had read elsewhere on this site that from firmware 1.22 that setting 2 digital lines was possible...is there anyway to access this functionality? The description above does not seem ready to handle the specification of two digital lines.
also...is there anyway to have the watchdog do a reset where the watchdog is disabled by the reset?
The U3 watchdog only controls
The U3 watchdog only controls 1 DIO. Perhaps you saw something about the UE9 as that controls 2 DIO. One common solution is to use "Config Defaults" in LJControlPanel to set the reset defaults of the device, and then use the watchog to reset the device. On the new T7 the watchdog can control all DIO.
This is the source of the
This is the source of the confusion...this was posted in january of 2011 by labjack support admin
OK, got to the bottom of this. The depreciated watchdog command is being called by the driver and not interpreted properly by the U3. The problem is that the depreciated command uses bit 4 of the settings byte to enable the DIO response where the other command uses bit 3 for one DIO and bit 4 for a second DIO. The result is that the second DIO was being enable and the first was being filled in. So, not only was EIO2 not changing, but FIO0 may have been changing.
A new beta firmware is available that moves the controlling bit accordingly. You can get Beta 1.36 here: http://labjack.com/s...irmware/u3/beta
I am using the low level commands on a linux system and if I follow the settings above, the watchdog DIO state setting does not work. Just for kicks and laughs, I set bit 3 instead of bit 4 and lo and behold...it now works as I expected. What is going on here? Is there a new watchdog command packet that does in fact have 2 DIO pins capable of being set in a timeout? If not, then why does using bit3 instead of bit4 work??? Is the above command packet correct???
All UD, U3, U6, UE9, devices
All UD, U3, U6, UE9, devices have been updated to support the extended watchdog function here: http://labjack.com/support/ue9/users-guide/53/53133-extended-watchdogconfig
If you have firmware 1.36 or later the above function should behave as documented.
I thought we had libs so that nobody had to worry about these things anymore. I will get someone familiar with Linux to chime in.
LabJackPython has a Watchdog
LabJackPython has a Watchdog function but it looks like its not the extended one, otherwise there are no Linux libs providing a high-level Watchdog function. Take a look at the extended-watchdog link we provided for the low-level command/response to use to set multiple digital I/O.