RM0390 Rev 4 429/1328
RM0390 Digital camera interface (DCMI)
448
Note: Camera modules can have 8 such codes (in interleaved mode). For this reason, the
interleaved mode is not supported by the camera interface (otherwise, every other
half-frame would be discarded).
• Mode 2
Four embedded codes signal the following events
– Frame start (FS)
– Frame end (FE)
– Line start (LS)
– Line end (LE)
The XY values in the 0xFF0000XY format of the four codes are programmable (see
Section 15.7.7: DCMI embedded synchronization code register (DCMI_ESCR)).
A 0xFF value programmed as a “frame end” means that all the unused codes are
interpreted as valid frame end codes.
In this mode, once the camera interface has been enabled, the frame capture starts
after the first occurrence of the frame end (FE) code followed by a frame start (FS)
code.
• Mode 1
An alternative coding is the camera mode 1. This mode is ITU656 compatible.
The codes signal another set of events:
– SAV (active line) - line start
– EAV (active line) - line end
– SAV (blanking) - end of line during interframe blanking period
– EAV (blanking) - end of line during interframe blanking period
This mode can be supported by programming the following codes:
• FS 0xFF
• FE 0xFF
• LS SAV (active)
• LE EAV (active)
An embedded unmask code is also implemented for frame/line start and frame/line end
codes. Using it, it is possible to compare only the selected unmasked bits with the
programmed code. You can therefore select a bit to compare in the embedded code and
detect a frame/line start or frame/line end. This means that there can be different codes for
the frame/line start and frame/line end with the unmasked bit position remaining the same.
Example
FS = 0xA5
Unmask code for FS = 0x10
In this case the frame start code is embedded in the bit 4 of the frame start code.
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