National Instruments 777937-01 Multifunction Timing and Digital I/O Module

The part number 777937-01 from National Instruments is the identifying part number for the PXI-6608 Multifunction Timing and Digital I/O Module. The 777937-01 features 32 configurable digital I/O channels which are TTL/CMOS-compatible lines in addtion to an Oven Controlled Crystal Oscillator which provides a stable 10 Mhz timebase essential for clock synchronization for the 777937-01 Module and other devices across the PXI system. 

Since the 777937-01 Multifunction Timing and Digital I/O Module is an oven controlled crystal oscillator it can create a use the 10 MHz for itself. The oven controlled crystal oscillator has an accuracy to the nearest 0.1 Hz from the nominal 10 Mhz frequency upon calibration and over time it has a minimal drift rate of 45 ppb per year.

The 777937-01 features eight 32 bit counter/timer channels. These counters can operate in various modes, including event counting, frequency measurement, period measurement, pulse generation, and more. The counters in the module have a 100 Kilohertz timebase as well as a 20 Megahertz time base for accurate clock signals and timing operations. These counters do support prescaling for high-frequency signals. 

The 777937-01 features a digital filtering option on its Programmable Function Interface lines to eliminate noise and glitches from the input signal and will only allow it for further processing once it gets stable after at least two consecutive rising edges of the filter clock. This filtering feature is necessary for the use of this module in environments with long signal cables and EMI noise. The 777937-01 Multifunction Timing and Digital I/O Module connects via the PXI backplane and includes three 68 pin VHDCI connectors for external signal interfacing. It supports flexible routing of timing signals through the PFI lines, allowing for easy configuration and reconfiguration without changing physical connections.