Video synchronization
There are two supported GPIO modes:
- Disabled (default). In disabled mode, no signals are provided as input or output on the GPIO pins.
- VSYNC enabled. In VSYNC mode, a video sync signal is provided as an output on GPIO3.
The VoSPI protocol is designed such that embedded timing signals are not required. However, the Lepton 3 does provide an optional 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 pulse is received.
The pulse is enabled by selecting
the VSYNC GPIO mode via the I2C CCI; when enabled, it is provided on the GPIO3 pin. The signal can be configured (also via the CCI) to lead or lag the actual internal start-of-segment (that is, the time at which the next segment is ready to be read) by -3 .. +3 line periods (approximately -1.5 .. 1.5 msec). By default, the pulse does not lead or lag.
| Name | Value | Description |
|---|---|---|
| Frequency (Oscilloscope) | 105.295 Hz | The frequency of new segments. A Lepton 3 frame consist of 4 segments. |
| Frequency (Datasheet) | 106 Hz | The frequency of new segments. A Lepton 3 frame consist of 4 segments. |
| Duration (High) | 73 µs | |
| Voltage (High) | 3.3v |