PCI_PCIe User Guide_RevA.pdf - Symmetricom

1.5. Dual-Port RAM Interface
Status Bits Summary
Bit
24
Description
Tracking (T)
0: Locked To Selected Reference
1: Flywheeling (Not Locked)
Phase (P)
25
0: < X Microseconds
1: > X Microseconds
X = 5 (Mode 0) X = 2 (All Other Modes)
Frequency (F)
26
0: < 5 x 10-8
1: > 5 x 10-8
27 Reserved
STATUS: Tracking (Bit 24)
This bit indicates that the TFP is not tracking the reference time source, usually because the time
source has been lost or has become unusable. When a timing Mode change occurs, this bit is set
until the TFP locks to the new timing source.
STATUS: Phase (Bit 25)
This bit indicates the synchronization accuracy of the TFP relative to the timing source. This bit is
updated approximately once per second. When the TFP's oscillator is synchronized to less than 5
microseconds with AM time code mode as a reference and less than 2 microseconds in other modes,
this bit is cleared.
STATUS: Frequency Offset (Bit 26)
This bit is an indication of the TFP on-board oscillator frequency offset relative to the timing source.
This bit reflects the short-term stability of the TFP's oscillator.
1.5. Dual-Port RAM Interface
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