FLIR Lepton 3.5 - Figure 40 - Intraframe Delay too Long - Failure to Read out an Entire Frame before the Next Is Available; Figure 41 - Failure to Read out an Available Frame; Vospi Protocol - Lepton 2 Vs. Lepton 3

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
62
Figure 40 - Intraframe Delay Too Long - Failure to Read Out an Entire Frame Before the Next is
Available
Figure 41 - Failure to Read Out an Available Frame
4.2.3.3.3 Frame Synchronization
The VoSPI protocol is designed such that embedded timing signals are not required. However, Lepton 3 does
provide an optional frame-timing output pulse that can aid in optimizing host timing. For example, the host can
burst-read data at a high clock rate and then idle until the next frame-timing pulse is received. The pulse is enabled
by selecting the VSYNC GPIO mode via the CCI; when enabled, it is provided on the GPIO3 pin (see GPIO Modes,
page 39). The signal can be configured (also via the CCI) to lead or lag the actual internal start-of-frame (that is,
the time at which the next frame is ready to be read) by -3 to +3 line periods (approximately -1.5 msec to +1.5
msec). By default, the pulse does not lead or lag.
4.2.4 VoSPI Protocol – Lepton 2 vs. Lepton 3
This section is provided for customers already familiar with the Lepton VoSPI protocol. It concisely summarizes
the difference between Lepton (80x60 resolution) and Lepton 3 (160x120 resolution). Much of the protocol is
identical, including the following:
1) The physical layer is identical, including the SPI mode and timing.
2) The minimum VoSPI transaction is a packet, consisting of 164 bytes of data when in Raw14 video mode or
244 bytes of data when in RGB888 mode. The packet protocol, including the packet header and payload,