1. PCI/PCIe TFP Hardware
1.1.2. Key Features
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All modes of operation are supplemented by flywheel operation. If the synchronization source is
lost, the TFP will continue to function at the last known reference rate. The following operational
modes are supported, and are distinguished by the reference source.
Mode Source of Synchronization
0
Time Code - IRIG A, B, G, E, IEEE 1344, NASA 36, XR3 & 2137
1
Free Running (Generator Mode) - 10 MHz Selected Reference (Internal or External)
2
1 PPS - External One Pulse Per Second Input
3
RTC-Uses battery backed on-board real time clock I.C.
4-5
Reserved
6
GPS (bc637) - GPS Antenna/Receiver
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Time may be captured in four independent sets of time capture registers. The default time format
is provided in binary form (UNIX seconds through 100 nanoseconds). The TFP Device Register
Summary and register formats are outlined in "TFP Device Register Summary" on page 27.
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In synchronized generator mode, the TFP uses the selected reference source to discipline either
the standard on-board TCXO (Temperature Compensated Crystal Oscillator), optional on-board
OCXO (Oven Controlled Crystal Oscillator) or external 10 MHz oscillator. The 10 MHz oscillator
drives all timing functions and outputs on the card. 10 MPPS and 1 PPS signals derived from the
10 MHz oscillator are provided as outputs, among others. The advantage of the OCXO is better
holdover (should the synchronization source be lost).
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The TFP generates IRIG A, B, G, E, IEEE 1344, NASA 36, XR3 and 137 time codes. Amplitude
modulated and DC level shift formats are produced simultaneously.
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A Programmable Periodic (also known as Heartbeat) output is provided. The output frequency is
programmable and may be synchronized to the TFP 1 PPS signal. The Periodic output pro-
gramming is discussed in"1.3.2. Heartbeat Output" on page 18. This signal may be internally con-
nected to the Event Input to capture the time associated with the Programmable Periodic edge.
The Event Input may be configured via the CONTROL Register as described in "CONTROL Reg-
ister (0x10)" on page 28. Note that the Periodic square wave output and the DDS square wave out-
put share the same output driver where either signal may be selected for output on J1 pin 15.
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A DDS (also known as frequency synthesizer) output may be selected in place of the periodic
rate generator's output. The DDS offers a much wider frequency range than the Programmable
Periodic. The DDS is discussed in more detail in "1.3.3. DDS Output" on page 19. Note that the
DDS and the Programmable Periodic signals are capable of generating interrupts. Caution should
be taken when using either of these sources with a rate that exceeds the computer's ability to
service the interrupts.
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A Time Coincidence Strobe output is provided. The Strobe is programmable from days through
microseconds. The strobe also has an each second mode (referred to in this manual as Minor
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