HP ADCS-2021, ADCS-1021 Datasheet

Description

The ADCS-1021 and ADCS-2021
CMOS Image Sensors capture
high quality, low noise images
while consuming very low power.
These parts integrate a highly
sensitive active pixel photodiode
array with timing control and
onboard A/D conversion. Avail­able in either VGA (640x480) or
CIF (352x288) resolution image
arrays, the devices are ideally
suited for a wide variety of
applications.

The ADCS-2021 and ADCS-1021,
when coupled with compatible
image processors from either
Agilent or selected Agilent
partners, provide a complete
imaging system to enable rapid
end-product development.
Designed for low-cost consumer
electronic applications, the
ADCS-2021 and ADCS-1021
sensors deliver unparalleled
performance for mainstream
imaging applications.

ADCS-2021 (VGA) and
ADCS-1021 (CIF) are CMOS active
pixel image sensors with inte­grated A/D conversion and full
timing control. They provide
random access of sensor pixels,
which allows windowing and
panning capabilities. The sensor
is designed for video conferencing

Agilent ADCS-1021, ADCS-2021
CMOS Image Sensors

Data Sheet

Key Specifications and Features

• High quality, low cost CMOS image
sensors

• Industry-standard 32-pin CLCC
package

• VGA resolution (640H x 480V)–

applications and still image
capabilities. The ADCS family
achieves excellent image quality
with very low dark current, high
sensitivity, and superior anti­blooming characteristics. The
devices operate from a single DC
bias voltage, are easy to configure
and control, and feature low
power consumption.

Programmable Features

• Programmable window size ranging
from the full array down to a 4 x 4
pixel window

• Programmable panning capability
which allows a specified window
(minimum 4x4 pixels) to be located
anywhere on the sensor array

• Integrated programmable gain
amplifiers with independent gain
control for each color (R, G, B)

• Internal register set programmable
via either the UART or Synchronous
serial interface

• Integrated timing controller with
rolling electronic shutter, row/
column addressing, and operating
mode selection with programmable
exposure control, frame rate, and
data rate

• Programmable horizontal, vertical,
and shutter synchronization signals

• Programmable horizontal and
vertical blanking intervals

ADCS-2021

• CIF resolution (352H x 288V)–
ADCS-1021

• High frame rates for digital video

VGA: 15 frames/second
CIF: 30 frames/second

• High sensitivity, low noise design
ideal for capturing high-quality
images in a variety of lighting
conditions

• Integrated analog-to-digital
converters:

VGA (ADCS-2021): 10 bit, programmable
CIF (ADCS-1021): 8 bit, fixed

• Parallel and serial output

• Automated, dark response
compensation

• Automatic subtraction of column
fixed pattern noise

• Still image capability

• Synchronous serial or UART
interface

• Integrated voltage references

Applications

• Digital still camera

• PC camera

• Handheld computers

• Cellular phones

• Notebook computers

• Toys

Brief Introduction

The Agilent ADCS-2021 and
Agilent ADCS-1021 image sen­sors act as normal CMOS digital
devices from the outside. Inter­nal circuits are a combination of
sensitive analog and timing
circuits. Therefore, the designer
must pay attention to the PC
board layout and power supply
design. Writing to registers via an

2

I

C compatible two-wire interface
provides control of the sensor.
Sensor data is normally output
via an 8 or 10 bit parallel inter­face (serial data output is also
available). Once the registers are
programmed the sensor is self­clocking and all timing is inter­nally generated. On chip pro­grammable amplifiers provide a
way to separately adjust the red
green and blue pixels for a good
white balance. Analog to digital
conversion is also on chip and 8
or 10 bit digital data is output. A
data ready pulse follows each
valid pixel output. An end of row
signal follows each row and an
end of frame signal follows each
frame.

PCB Layout

Analog Vdd and analog ground
need to be routed separately
from digital Vdd and digital
ground. Noisy circuits or ICs
should not be placed on the
opposite side of the PC board.
Heat producing circuits such as
microprocessors or LCD displays
should not be placed next to or
opposite from the sensor to
reduce noise in the image.

Power Supply

The sensor operates at 3.3 VDC.
There are two power supplies for
the sensor. Analog V

dd

and
Digital Vdd. The two supplies and
grounds must be kept separate.
Two separate regulators provide
the best isolation. Any noise on
the analog supply will result in
noise in the image. Analog and
digital ground should be tied
together at a single point of
lowest impedance and noise.

Master Clock

The part requires a 50% duty cycle
master clock. Maximum clock
rates are 25 MHz for ADCS-2021
and 32 MHZ for ADCS-1021.

Reset

A hard reset is required before
the sensor will function properly.
Once the master clock is running,
assert nRST_nSTBY for 40 clock
cycles.

Register Communication

Communication (read/write) to
the sensor registers is via a two
wire serial interface — either a
synchronous I2C compatible or
half duplex UART (9600 baud
default). nTristate (pin 3
ADCS-1021 only) must be pulled
high for normal operation. The
ADCS-2021 does not have
nTristate.

Parallel Data Output

8 or 10 bit parallel data is output
from the sensor. A data ready
line (DRDY) is asserted when the
data is valid. The sensor acts as a
master in the way it outputs
data. There is no flow control or
data received handshake. Once
the RUN bit (CONTROL register)
is set, the image processor must
be ready to accept data at the
sensor rate and when the data is
presented.

Serial Data Output

In this mode, output data lines
D0 and D1 (the lower two bits of
the parallel data port) act as a
two wire serial interface.

Handshaking

At the end of one row of data, the
nROW line is asserted. At the end
of one frame of data, the
nFRAME_nSYNC line is asserted.

Registers

On the next page is a table of
sample register settings (see
Figure 1). These values are a
good starting point.

2

Table 1. Register Set Declaration for Agilent ADCS-1021 and ADCS-2021 Image Sensors.

Register Name Mnemonic Address (hex) Sample Value (hex)

Identifications Register IDENT 0x00

Status Register STATUS 0x01 0x7F

Interrupt Mask Register IMASK 0x02 0x00

Pad Control Register PCTRL 0x03 0x03

Pad Drive Control Register PDRV 0x04 0x00

Interface Control Register ICTRL 0x05 0x20

Interface Timing Register ITMG 0x06 0x00

Baud Fraction Register BFRAC 0x07 0x00

Baud Rate Register BRATE 0x08 0x00

ADC Control Register ADCCTRL 0x09 0x08

First Window Row Register FWROW 0x0A 0x00

First Window Column Register FWCOL 0x0B 0x07

Last Window Row Register LWROW 0x0C 0x79

Last Window Column Register LWCOL 0x0D 0xA8

Timing Control Register TCTRL 0x0E 0x04

PGA Gain Register: Green ERECPGA 0x0F 0x00

PGA Gain Register: Red EROCPGA 0x10 0x00

PGA Gain Register: Blue ORECPGA 0x11 0x00

PGA Gain Register: Green OROCPGA 0x12 0x00

Row Exposure Low Register ROWEXPL 0x13 0x00

Row Exposure High Register ROWEXPH 0x14 0x02

Sub-Row Exposure Register SROWEXP 0x15 0x00

Error Control Register ERROR 0x16 0x00

Interface Timing 2 Register ITMG2 0x17 0x4B

Interface Control 2 Register ICTRL2 0x18 0x00

Horizontal Blank Register HBLANK 0x19 0x00

Vertical Blank Register VBLANK 0x1A 0x00

Configuration Register CONFIG 0x1B 0x0C

Control Register CONTROL 0x1C 0x04

Reserved 0x1D —

Reserved 0x1E —

Reserved 0x1F —

Reserved 0x20 —

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