PT1

Pulse Timer Receiver and Generator

The PT1 pulse timer receiver and generator module facilitates synchronization of an effective range of 1 PPS to 10 MHz signal input and provides capability for host processor RTC time stamping, other timer sync and output signal generation to other modules, boards and/or system components. The PT1 provides multiple inputs and outputs to suit varying system requirements.

The PT1 provides (2) independently programmable input channels, each of which can be used for an effective range of 1 PPS to 10 MHz signal input. If desired, two PPS signals can be input, and the user can select which one to use, or automatically switch from input ‘a’ to ‘b’ (or vice-versa) if one signal input is ‘lost’. Inputs have a programmable threshold reference voltage range, from -10V to +10V for single ended (SE). Input impedance is also selectable/programmable, to match source drive impedance.

The PT1 also provides (8) outputs to provide a choice of either standard TTL SE, RS-422 DF, 5 V @ Z = 50-ohm, or 12 V @ Z = 50-ohm. This provides capability for the PT1 to re-distribute the PPS input to other devices directly.

The 1 PPS to 10 MHz input signals are also made available to the motherboard for direct connection to other modules on that board (support pending) as well to the motherboard processor (for interrupt and/or other bus handling).

Additionally, there are two independent isolated asynchronous RS-422/485 serial ports available for communications. The two ports are functionally identical to the NAI SC3 serial communications module for asynchronous communications interface modes including independent TX and RX FIFO buffers and programmable baud rates up to 1 Mbps.

Features

• 2 Inputs: 1PPS to 10 MHz, inclusive, Independently Programmable; Signal-ended or differential: -24 V to +24 V (differential), -10 V to + 10 V (single ended); general input characteristics: Zin programmable: 50, 75, 100 or high-Z (high-Z being ~ 100 kohms); Input capacitance: ~ 50 pF
• 8 Outputs: 2 Ch. TTL level signals, ±24 mA (max.); 2 Ch. RS-422 signals; 2 Ch. 5 V signals (capable of driving 50-ohm load); 2 Ch. 12 V signals (capable of driving 50-ohm load)
• 2 Independent RS-422/485 Isolated Asynchronous Serial Communications Ports: Programmable high speed data rates up to 1 Mbps; 1KB (x 16) receive and transmit buffers
• Application Features: Module will also "send" the 1 PPS to 10 MHz signals to the motherboard for direct connection to other modules on that board and to the motherboard processor (pending); Direct motherboard processor IRQ capability for deterministic, low latency time-sync (motherboard support req'd); Direct SMA coax, for special Zin matched or additional shielding requirements (pending).