Datasheet

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SLAS326A − JANUARY 2001 − REVISED MARCH 2004

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

optical black setup register format

D9 D8 D7 D6 D5 D4 D3 D2 D1 D0

OMUX1 OMUX0 HYS X SOFW1 SOFW0 MP PN2 PN1 PN0

optical black setup register description

BIT NAME DESCRIPTION

D8, D9 OMUX1,

OMUX0

These two bits multiplex digital output (data presented at D[9:0] pins):

OMUX1 OMUX0

0 0 D[9:0] = ADC output (default)

0 1 D[9:0] = ADC output

1 0 D[9] = fine/coarse (1/0) autocorrection flag

D[8] = coarse DAC sign

D[7:0] = coarse DAC value

1 1 D[9] = fine/coarse (1/0) autocorrection flag

D[8] = fine DAC sign

D[7:0] = fine DAC value

D7 HYS Sets the hysteresis

0 − Apply hysteresis to FDAC (default)

1 − No hysteresis

D6 X Reserved

D5, D4 SOFW1,

SOFW0

These two bits set the digital filter weight when SOF is activated (the SOF bit in control register 2 is set to 1).

SOFW1 SOFW0 Weight

0 0 0 (default)

0 1 1

1 0 2

1 1 3

D3 MP When this bit is 1, the number of optical black pixels to be averaged per line (2

) is multiplied by 3.

By setting the MP and PN2−PN0 bits together, the number of optical black pixels can be programmed to have the follow-

ing numbers:

1, 2, 3 (1X3), 4, 6 (2×3), 8, 12 (4×3), 16, 24 (8×3), 32, 48 (16×3), 64, 96 (32×3), and 192 (64×3).

Default: MP = 0, no multiplication

D2−D0 PN2−PN0 Number of optical black pixels per line to average = 2

N can be 0, 1, 2, 3, 4, 5, and 6. Or number of pixels per line can be 1, 2, 4, 8 (default), 16, 32, or 64.

The maximum number of pixels per line is 64, even if N>6.

Default optical black calibration register value = 0000000011