ASX340AT_16 Datasheet, PDF (32/54 Pages) ON Semiconductor – 1/4‐inch Color CMOS NTSC/PAL Digital Image SOC

ASX340AT
The position of the target will be used to determine the
calibration value that shifts the row and column position of
adjustable overlay graphics.
The overlay calibration is intended to be applied on a
device by device basis “in system,” which means after the
camera has been installed. ON Semiconductor provides
basic programming scripts that may reside in the SPI Flash
memory to assist in this effort.
OVERLAY CHARACTER GENERATOR
In addition to the four overlay layers, a fifth layer exists
for a character generator overlay string.
There are a total of:
• 16 alphanumeric characters available
• 22 characters maximum per line
• 16 x 32 pixels with 1-bit color depth
Any update to the character generator string requires the
string to be passed in its entirety with the Host Command.
Character strings have their own control properties aside
from the Overlay bitmap properties.
Overlay
Register Bus
DMA/CPU
Data Bus
User Registers
Timing control
BT656
Layer3
Layer2
Layer1
Layer0
ROM
BT656
Figure 31. Internal Block Diagram Overlay
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