HB7121B

Semiconductor Inc.

CMOS IMAGE SENSOR

System IC SBU

With 8-bit ADC

This document is a general product description and is subject to change without notice. Hynix Semiconductor does not assume

any responsibility for use of circuits described. NO patent licenses are implied.

DA21000601R_1.0

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2001 Hnix System IC SBU

(14) Pixel Bias Voltage Register (Address 34h, default:02h, R/W)

This register controls pixel reference level by controlling bias current of pixel output sensing load

transistor. It controls pixel output level itself, compare with that revel register adjust A/D Converter

circuit to calibrate reference level for data reading. Available program range is 0 ~ 7. The larger

register value causes the higher bias current and low pixel output reference level. This register is

option for manufacturer. Users may use default setting and don’t changed value.

(15) Low Reference Number Register(low_ref_no)

High : (Address 57h default:00h, Read Only)

Low : (Address 58h, default:00h, Read Only)

Low Reference Number Registers indicates number of pixels in frame that have a value less then 5.

A reference level values of each pixel is compare with ‘5’, and accumulated to these registers

during read state. This counter value called low_ref_no, consist of two bytes and it is read only

registers. Real number of pixels that have value less than 5 is the twice of these register value. If

low_ref_no is big value, you must increase data value of Reset Level Control Register. These

registers are updated after every VSYNC signal.

(16) High Reference Number Register (high_ref_no)

High : (Address 59h, default:00h, Read Only)

Low : (Address 5Ah, default:00h, Read Only)

High Reference Number Registers indicates number of pixels in a frame that have a value great then

123. Reference level values of each pixels is compared with ‘123’, and accumulated to these

registers during read state. This counter value called high_ref_no, consist of two bytes and it is read

only registers. Real number of pixels that have value great than 123 is the twice of these register

value. If high_ref_no is big value, you must decrease data value of Reset Level Control Register.

These registers are also updated after every VSYNC signal.