13.2 DIO Extended Features [T-Series Datasheet]

DIO-EF Enable/Disable

This register is used to disable a DIO-EF feature (in order to configure it) and also used to start or enable the DIO-EF subsystem.

A DIO-EF doesn't always need to be disabled for it to be configured, depending on the DIO-EF being enabled.

DIO-EF Index (Feature Selection)

This register is used to select the extended feature that will get enabled on a given DIO line. The valid DIO lines differ by device. For more specific details look at reference tables 13.2-1 and 13.2-2 as well as the appropriate DIO-EF feature subsection.

DIO-EF Options and Clock Source Selection

This register isn't used by all DIO-EF features.

If a DIO-EF feature requires the configuration or selection of a clock source (such as PWM Out does), the configuration of this register is required, since it is required for selecting a clock source. See 13.2.1 EF Clock Source for more details about clock source selection.

DIO-EF Configuration

Configuration registers serve two purposes. They provide a location for settings that need to be configured upon DIO-EF enable and they provide a location for settings that users may need to use to update a DIO-EF feature once it has been enabled.

Initial Configuration: Configuration is the initial setup of the Extended Feature. Configuration requires that any DIO-EF running at the pin in question first be disabled. Options can then be loaded. Then the DIO-EF can be enabled.

Update: Some DIO#_CONFIG registers can be updated while a DIO-EF is running. Updating allows the DIO-EF to change its operation parameters without restarting. Note that the clock source and feature index cannot be changed in an update. Depending on the feature, reads and writes to the update registers have small differences. See the Update portion of each feature for more information.

DIO-EF Basic Read Registers

Some DIO-EF produce results or provide status information that can be read. This information is usually a binary integer. When possible, the T-series device will convert the binary integer into a real-world unit such as seconds. When available, converted values can be read from the registers designated with “_F”.

DIO-EF Read-and-Reset Registers

Some DIO-EF can be reset while they are running. Resetting can have different results depending on the feature. For instance, counters are reset to zero.

Streaming DIO-EF Results

Though all operations discussed in this section are supported in command-response mode, some DIO-EF features can be read fast enough to be streamed:

• Frequency In
• Pulse Width In
• High-Speed Counter
• Interrupt Counter
• Interrupt Counter with Debounce
• Quadrature In
• Interrupt Frequency In

In stream mode, you can read from the integer READ registers (A, B, A_AND_RESET), but as mentioned in 3.2 Stream, those reads only return the lower 16 bits so you need to also use STREAM_DATA_CAPTURE_16 in the scan list to get the upper 16 bits.

Other Considerations

Specifications

See Appendix A-2 for specs including:

• Frequency Output
• Counter Input Frequency
• Minimum High & Low Time
• "Interrupt" Total Edge Rate

System Timer

Complications can occur if streaming while enabling a DIO-EF that requires the use of a system timer. Please contact LabJack support if you need to do this.

Available DIO-EF By Device/Reference Tables

T4

T7

* Line-to-Line In and Quadrature In both require two DIO lines.