FLIR Lepton 1.6 - Figure 37 - Frame Counter for Successive Frames

FLIR LEPTON® Engineering Datasheet
The information contained herein does not contain technology as defined by the EAR, 15 CFR 772, is publicly available,
and therefore, not subject to EAR. NSR (6/14/2018).
Information on this page is subject to change without notice.
Lepton Engineering Datasheet, Document Number: 500-0659-00-09 Rev: 203
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with US export restrictions. For each unique frame, two partial and invalid frames follow in the VoSPI stream. This
pattern is illustrated in Figure 37, with unique frames shown in blue and invalid frames shown in gray. The 32-bit
frame counter provided in the telemetry lines (see Telemetry Modes, page 23) only increments on new frames,
which is also illustrated in Figure 37. The segment numbers will follow accordingly: 1, 2, 3, 4, 0, 0, 0, 0, 0, 0, 0, 0,
1, 2, 3, 4, etc., where unique frames are comprised of segment numbers 1, 2, 3, 4 and invalid frames are
comprised of zeros for each segment number.
Figure 37 - Frame Counter for Successive Frames
NOTE: Blue frames are different than the previous frames, gray frames are invalid.
4.2.3.3.1 Establishing/Re-Establishing Sync
The basic process for establishing synchronization is listed below:
• Deassert /CS and idle SCK for at least 5 frame periods (>185 msec). This step ensures a timeout of the
VoSPI interface, which puts the Lepton 3 in the proper state to establish (or re-establish) synchronization.
• Assert /CS and enable SCLK. This action causes the Lepton 3 to start transmission of a first packet.
• Examine the ID field of the packet, identifying a discard packet. Read out the entire packet.