The DT4 module (the enhanced version) features 24 programmable channels for either input (voltage or contact sensing with programmable, onmodule pull-up/pull down current sources), or output (current source, sink, or push-pull) up to 500 mA per channel from an applied, external 3 – 60 VCC source. These modules can sense broken input connections and whether an input is shorted to +VCC or to ground. Additional features of the DT4 (Enhanced Version) are listed below.

Features

•24 channels available as inputs or outputs

•Ability to handle high inrush current loads (for example, two #327 incandescent lamps in parallel)

•Built-In-Test runs in background constantly monitoring system health for each channel

•Programmable for Input (voltage or contact sensing) or Output (current source, sink or push-pull) per channel/bank

•Supports 'dual turn-on' (series channel output) applications (for example, dual series 'key' missile launch control)

•Ability to sense broken input connection and if input is shorted to +V or to ground

•Ability to current share, by connecting multiple outputs in parallel, to sink/source up to 2 A per bank*

•Programmable debounce circuitry with selectable time delay eliminates false signals resulting from relay contact bounce

•Ability to read I/O voltage and output current for improved diagnostics (indicates if load is connected)

•Enhanced DT4 Functionality Features:

Additional Enhanced Input Mode

Operation: Pulse Measurements,

Transition Timestamps, Transition

Counters, Period Measurement and

Frequency Measurement

Additional Enhanced Output Mode

Operation: PWM Output and Pattern

Generator Output

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NAI’s Custom-On-Standard Architecture™ (COSA®) offers a choice of over 40 Intelligent I/O, communications, or Ethernet switch functions, providing the highest packaging density and greatest flexibility of any 3U SBC in the industry. Preexisting, fully-tested functions can be combined in an unlimited number of ways quickly and easily.

The 75PPC1 includes BSP and SDK support for Wind River® VxWorks®. In addition, software support kits are supplied, with source code and board-specific library I/O APIs, to facilitate system integration. Each I/O function has dedicated processing, unburdening the SBC from unnecessary data management overhead.

BIT continuously monitors the status of all I/O during normal operations and is totally transparent to the user. SBC resources are not consumed while executing BIT routines. This simplifies maintenance, assures operational readiness, reduces life-cycle costs and— keeps your systems mission ready.

Eliminate man-months of integration with a configured, field-proven system from NAI. Specification to deployment is a seamless experience as all design, state-of-the-art manufacturing, assembly and test are performed— by one trusted source. All facilities are in the U.S. and optimized for high-mix/low volume production runs and extended lifecycle support.

From design-in to production, and beyond, NAI’s product lifecycle management strategy ensures the long-term availability of COTS products through configuration management, technology refresh, and obsolescence component purchase and storage.

As a leading manufacturer of smart function modules, NAI offers over 100 different modules that cover a wide range of I/O, measurements and simulation, communications, Ethernet switch, and SBC functions. Our enhanced function (EF) discrete I/O multichannel smart function modules provide the same interfacing solutions for almost embedded or test application (unparalleled programming flexibility, wide range of operating characteristics, unique design that eliminates the need for pull-up resistors or mechanical jumpers) as the standard function (SF) version. Additionally, the EF module adds built-in functionality to provide Pulse/Frequency Period Measurements of the incoming signal (input) and/or Pulse/Frequency arbitrary signal generation (output). This user manual is designed to help you get the most out of our discrete I/O smart function modules.

NAI’s DT4 module offers a range of features designed to suit a variety of system requirements, including:

•24 Channels of Programmable Discrete Input/Output:

The DT4 module features 24 channels programmable for either discrete input or output that provide the following: •Input – voltage or contact sensing with programmable, pull-up/pull-down current sources, eliminating the need for external resistors or mechanical jumpers. •Output – programmable current source (high-side), sink (low-side) or push-pull switching up to 500 mA per channel from an applied 3- 60V external VCC source (or sink to ISO-GND).

The module enables current sharing* by connecting multiple outputs in parallel, capable of sinking or sourcing up to 2A per bank, enhancing your system’s capacity and reliability. (*) Current Share: The maximum output load per-channel is ±0.5A. Channels can be connected and operated in parallel to provide > 0.5A to act as a single channel. The load current between paralleled channels cannot be effectively characterized and is not expected to be equal due to factors including: Channel/bank position, module position, motherboard/system platform configuration, operating temperature range including external application/configuration influences (e.g., external cabling). Therefore, when operating in shared current (parallel channel) configuration, it is recommended to de-rate the per-channel maximum current output to at least 66% (or 333 mA/channel) to ensure that no single channel is overburdened by handling most of the load current. For example: If the maximum continuous load current is expected to be 1A: 1/0.33 ≅ 3 channels (minimum).

The DT4 module can efficiently handle high inrush current loads, such as connecting two #327 incandescent lamps in parallel, without compromising performance.

The module supports ‘dual turn-on' applications, such as dual series ‘key' missile launch control, providing seamless control in critical operations.

Programmable debounce circuitry with selectable time delay eliminates false signals caused by relay contact bounce, ensuring accurate data acquisition.

All channels have continuous background Built-In-Test (BIT), which provides real-time channel health to ensure reliable operation in mission-critical systems. This feature runs in the background and is transparent in normal operations.

The DT4 module can sense broken input connections and detect if inputs are shorted to +V or ground, allowing for early detection and troubleshooting.

The module offers the ability to read I/O voltage and output current, facilitating improved diagnostics and load status identification (indicates if load is connected).

In addition to offering the same functionality as the DT1 standard function (SF) module, the DT4 includes the following enhanced features: •Enhanced Input Mode – Pulse Measurements, Transition Timestamps, Transition Counters, Period Measurement, and Frequency Measurement. •Enhanced Output Mode – PWM Output and Pattern Generator Output.

DT4 provides up to 24 individual digital I/O channels with BIT fault detection, which enables flagging of non-compliant outputs or inconsistent input readings between dual input measurements

When channels are programmed as inputs, they can be used for either voltage or contact sensing. Channels set for contact sensing (e.g., sensing a relay contact position; OPEN-CLOSED) can be configured with a programmable “pull-up” or “pull-down” (current source or sink) which effectively provides the proper voltage level change to sense the open state of the contact. This unique design eliminates the need for external resistors or mechanical jumpers. Instead, this design offers a current source/sink (in banks of 6 channels) that the user programs to a desired current (0-5 mA) level.

When programmed as outputs, each channel can be set for high-side (current-source), low-side (current-sink) or push-pull (current-source-sink) operation. The load impedance determines the delivered switched output current drive – up to 500 mA per channel. Diode clamping is provided (useful for inductive loads, such as relays) and thermal protection.

Overcurrent protection is implemented using current sensing technology. When the current exceeds a programmed threshold of 650 mA steadystate, or a higher short duration, the overcurrent/short-circuit protection is triggered, shutting down the output drivers for safety. The overcurrent fault status will be indicated for the affected channels and will require a reset operation to restore output. To reset this condition, a reset command needs to be issued to the Overcurrent Reset register, which will restore drive output and allow the latched status to be reset. This is separate from the reset for the Overcurrent Interrupt Enable register on this module. It is recommended that a reset command is done whenever status is cleared to avoid a non-apparent output reset condition.

The 24 channels are configured as 4 banks of 6 channels. Each bank is provided with a separate external input VCC and a ground return (GND) pin. The GND pins are common within the module but are isolated from system (power) GND.

•An external source VCC supply must be wired for proper: •Output operation as a current source •Input operation when requiring a programmed pull-up current (i.e., programmed “pull-up” for input contact sense; OPEN/GND detect/state change). •An external source Ground/Return must be wired for all I/O configurations. The Ground/Return must be the input signal or the load current sink ground/reference.

Each channel can be configured as an input or one of three types of outputs.

When configured as an output, the interface can act as a “High-Side”, “Low-Side” or “Push-Pull” drive, providing up to 500 mA per channel or 1 A when two channels are connected in parallel. The total output per module is 8 A (2 A per bank).

Note: Maximum source current ‘rules' for rear I/O connectors still apply – see specifications.

When configured as an input, output drivers are disabled. The I/O interface can act as a constant current source, current sink or voltage sensing circuit. For contact sensing, each channel may be set for pull-up or pull-down using the Select Pull-Up or Pull-Down register and by entering the appropriate current level in the Pull-Up/Down Current register. Contact closure and hysteresis may be defined using the Upper Voltage and Lower Voltage Threshold registers. No additional resistors or hardware are required to provide for current flow. A current value of zero disables the current source/sink circuits and configures the module for voltage sensing. Default is voltage sensing. Level or contact sensing can be mixed within a channel bank, if the contact sensing channels are externally pulled up or pulled down.

Note: If this module supplies the current for the contact sensing, then level and contact sensing cannot be mixed within a channel bank.

All four threshold levels must be programmed in monotonic, increasing order of: Minimum Low, Lower, Upper and Maximum High. For input and output, threshold levels define logic state. For output, threshold levels are used in BIT test (wrap-around) signal monitoring. A pair of drive FETs and current circuits are provided at each I/O pin. See the functional representation of the drivers in the I/O Circuits interface diagram below.

Four threshold levels: Max High Voltage Threshold, Upper Voltage Threshold, Lower Voltage Threshold, and Min Low Voltage Threshold offer maximum user flexibility. All four threshold levels must be programmed. For input or output, the threshold levels will define the logic states. For proper operation, the threshold values should be programmed such that:

Max High Voltage Threshold > Upper Voltage Threshold > Lower Voltage Threshold > Min Low Voltage Threshold

Program Upper and Lower Voltage Thresholds, keeping the 0.25 V min. differential in mind, and then add debounce time as required. When the input signal exceeds the Upper Voltage Threshold, a logic high 1 is maintained until the input signal falls below the Lower Voltage Threshold. Conversely, when the input signal falls below the Lower Voltage Threshold, a logic low 0 is maintained until the input signal rises above the Upper Voltage Threshold.

=Debounce Programming The Debounce register, when programmed for a non-zero value, is used with channels programmed as input to “filter” or “ignore” expected application spurious initial transitions. Once a signal level is a logic voltage level period longer than the Debounce Time (Logic High and Logic Low), a logic transition is validated. Signal pulse widths less than programmed Debounce Time are filtered. Once valid, the transition status register flag is set for the channel and the output logic changes state.

The Discrete module supports automatic background BIT testing that verifies channel processing. The testing is totally transparent to the user, requires no external programming and has no effect on the operation of the module. This capability is accomplished by an additional test comparator that is incorporated into each module. The test comparator checks each channel and is compared against the operational channel. Depending upon the configuration, the Input data read, or Output logic written of the operational channel and test comparator must agree or a fault is indicated with the results available in the associated status register. The results of the tests are stored in the BIT Dynamic Status and BIT Latched Status registers.

The technique used by the continuous background BIT (CBIT) test consists of an “add-2, subtract-1” counting scheme. The BIT counter is incremented by 2 when a BIT-fault is detected and decremented by 1 when there is no BIT fault detected and the BIT counter is greater than 0. When the BIT counter exceeds the (programmed) Background BIT Threshold value, the specific channel’s fault bit in the BIT status register will be set. Note, the interval at which BIT is performed is dependent and differs between module types. Rather than specifying the BIT Threshold as a “count”, the BIT Threshold is specified as a time in milliseconds. The module will convert the time specified to the BIT Threshold “count” based on the BIT interval for that module. The “add-2, subtract-1” counting scheme effectively filters momentary or intermittent anomalies by allowing them to “come and go“ before a BIT fault status or indication is flagged (e.g., BIT faults would register when sustained; i.e., at a ten second interval, not a 10-millisecond interval). This prevents spurious faults from registering valid such as those caused by EMI and/or dirty power causing false BIT faults. Putting more “weight” on errors (“add-2”) and less “weight” on subsequent passing results (subtract-1) will result in a BIT failure indication even if a channel “oscillates” between a pass and fail state.

In addition to BIT, the Discrete module tests for overcurrent conditions and provides Above Max High Voltage, Below Min Low Voltage, and MidRange Voltage statuses for threshold signal transitioning.

The DT Discrete I/O Function Module provide registers that indicate faults or events. Refer to “Status and Interrupts Module Manual” for the Principle of Operation description.

The Discrete I/O Function Module includes module common registers that provide access to module-level bare metal/FPGA revisions & compile times, unique serial number information, and temperature/voltage/current monitoring. Refer to “Module Common Registers Module Manual” for the detailed information.

The Discrete Module Threshold and Measurement registers can be programmed to be utilized as a single precision floating point value (IEEE-754) or as a 32-bit integer value. The purpose for providing this feature is to offload the processing that is normally performed by the mission processor to convert the integer values to floating-point values.

When the Enable Floating Point Mode register is set to 1 (Floating Point Mode) the following registers are formatted as Single Precision Floating Point Value (IEEE-754): •Voltage Reading (Volts) •Current Reading (mA) •VCC Voltage Reading (Volts)

•Max High Voltage Threshold (Volts)

•Upper Voltage Threshold (Volts)

•Lower Voltage Threshold (Volts)

•Min Low Voltage Threshold (Volts)

•Pull-Up/Down Current (mA)

*When the Enable Floating Point Mode register is set to 1, it is important that these registers are updated with the Single Precision Floating Point (IEEE-754) representation of the value for proper operation of the channel. Conversely, when the Enable Floating Point Mode register is set to 0, these registers must be updated with the Integer 32-bit representation of the value.

Note: when changing the Enable Floating Point Mode from Integer Mode to Floating Point Mode or vice versa, the following steps are followed to avoid faults from falsely being generated: 1. Set the Enable Floating Point Mode register to the desired mode (Integer or Floating Point). 2. The application waits for the Floating Point State register to match the value for the requested Floating Point Mode (Integer = 0, Floating Point = 1); this indicates that the module’s conversion of the register values and internal values is complete. Data registers will be converted to the units specified and can be read in that specified format.

The Discrete Modules provide registers that support User Watchdog Timer capability. Refer to “User Watchdog Timer Module Manual” for the Principle of Operation description.

The DT4 Module provides enhanced input and output mode functionality. For incoming signals (inputs), the DT4 enhanced modes include Pulse Measurements, Transition Timestamps, Transition Counters, Period Measurement and Frequency Measurement. For outputs, the DT4 enhanced modes include PWM (Pulse Width Modulation) Outputs and Pattern Generator Outputs.

Refer to “Enhanced Discrete I/O, Digital I/O Functionality – Module Manual” for the Principle of Operation description.

The register descriptions provide the register name, Type, Data Range, Read or Write information, Initialized Value, a description of the function and, in most cases, a data table.

Each channel can be configured as an input or one of three types of outputs. The I/O Format (Ch1-16 and Ch17-24) registers are used to set each channel input/output configuration. The Write Outputs register controls the output channels to either a High (1) or Low (0) state, and the Read I/O register contains the discrete channel’s state (High (1) or Low (0)) as specified by the channel’s threshold configurationss.

Four threshold levels: Max High Voltage Threshold, Upper Voltage Threshold, Lower Voltage Threshold, and Min Low Voltage Threshold are programmable for each Discrete channel in the module.

Max High Voltage Threshold (Enable Floating Point Mode: Integer Mode) Upper Voltage Threshold (Enable Floating Point Mode: Integer Mode) Lower Voltage Threshold (Enable Floating Point Mode: Integer Mode) Min Low Voltage Threshold (Enable Floating Point Mode: Integer Mode)

Max High Voltage Threshold (Enable Floating Point Mode: Floating Point Mode) Upper Voltage Threshold (Enable Floating Point Mode: Floating Point Mode) Lower Voltage Threshold (Enable Floating Point Mode: Floating Point Mode) Min Low Voltage Threshold (Enable Floating Point Mode: Floating Point Mode)

The measured voltage and current at the I/O pin for each channel can be read from the Voltage Reading and Current Reading registers.

There are four VCC banks where each bank controls 6 discrete channels. Configuration for each bank involves specifying if the bank is configured for pull-up or pull-down and the current for source/sink. The measured voltage for each VCC bank can be read from the VCC Voltage Reading register.

Control of the Discrete I/O channels include specifying the Debounce time for each input channel and resetting the I/O channel on an overcurrent condition.

The Enable Floating Point register provides the ability to set the Threshold values as floating-point values and read the Voltage Reading and Current Reading registers as floating-point values. The purpose for this feature is to offload the processing that is normally performed by the mission processor to convert the integer values to floating-point values.

The Background BIT Threshold register provides the ability to specify the minimum time before the BIT fault is reported in the BIT Status registers. The BIT Count Clear register provides the ability to reset the BIT counter used in CBIT.

Refer to “User Watchdog Timer Module Manual” for the Register descriptions.

Refer to “Module Common Registers Module Manual” for the register descriptions.

The Discrete Module provides status registers for BIT, Low-to-High Transition, High-to-Low Transition, Overcurrent, Above Max High Voltage,Below Min Low Voltage, and Mid-Range Voltage

Key: Bold Italic = Configuration/Control

Bold Underline = State/Measurement/Status

When an event is detected, the bit associated with the event is set in this register and will remain set until the user clears the event bit. Clearing the bit requires writing a 1 back to the specific bit that was set when read (i.e., write-1-to-clear, writing a “1” to a bit set to “1” will set the bit to “0). * Data is represented in Floating Point if Enable Floating Point Mode register is set to Floating Point Mode (1).

Pull-Up/Down Current

VCC Voltage Reading

Refer to “User Watchdog Timer Module Manual” for the User Watchdog Timer Status Function Register Map.

Refer to “Module Common Registers Module Manual” for the Module Common Registers Function Register Map.

BIT Status

Voltage Reading Error

Low-to-High Transition Status

High-to-Low Transition Status

Overcurrent Status

Above Max High Voltage Status

Below Min High Voltage Status

Mid-Range Voltage Status

User Watchdog Timer Fault Status

The Discrete Modules provide registers that support User Watchdog Timer capability. Refer to “User Watchdog Timer Module Manual” for the User Watchdog Timer Fault Status Function Register Map.

Summary Status

Refer to “Enhanced Discrete I/O, Digital I/O Functionality – Module Manual” for the Function Register Map

The Interrupt Vector and Interrupt Steering registers are located on the Motherboard Memory Space and do not require any Module Address Offsets. These registers are accessed using the absolute addresses listed in the table below.