VV5430

Write to Camera

CD5430F-A

27/33

Header Code (fine)

= 0100

Valid data bits: 9

The 18 bit exposure control value is formed from two 9-bit values, coarse (9 msb’s) and fine (9 lsb’s). For external exposure

control (AEC = 0) the exposure value can be set via the serial interface (header codes 0011 and 0100). Values written that

exceed the mode dependant maxima will be ignored and the maximum will be used.

Exposure Control Thresholds T1 and T2

Header Code (T1)

= 1000

Valid data bits: 9

Header Code (T2)

= 1001

Valid data bits: 9

The lower and upper pixel count thresholds are used by the automatic exposure controller. The power-on default values for T1

and T2 are exposure mode and video mode dependant. If the external pixel threshold control bit (bit 6 in Setup Code_2 register)

is set the internal default values for T1 and T2 are overridden by the serial interface values. Note that only the most significant

nine bits of each seventeen bit threshold can be controlled.

Bit

Function

CCIR

min

max

EIA

min

max

Comments

0-8

Coarse exposure value

0

310

0

260

Header code 0011

0-8

Fine exposure value

0

404

0

325

Header code 0100

9-11

Unused

Table 18 : Exposure Values

Bit

DAC

Comments

0 - 8

Lower Exposure control threshold (T1)

Header Code 1000

0 - 8

Upper Exposure control threshold (T2)

Header Code 1001

9 - 11

Unused

Table 19 : Pixel Count Thresholds (T1,T2)