OV2640 Camera Module Hardware Application Notes

OmniVision Technologies, Inc. reserves the right to make changes without further notice to
any product herein to improve reliability, function or design. OmniVision does not assume
any liability arising out of the application or use of any project, circuit described herein;
neither does it convey any license under its patent nor the right of others.

This document contains information of a proprietary nature. None of this information shall
be divulged to persons other than OmniVision Technologies, Inc. employee authorized by
the nature of their duties to receive such information, or individuals or organizations
authorized by OmniVision Technologies, Inc.

1. OV2640 Camera Module Reference Design

   NOTE:
   Connector PWDN should be connected to ground if unused.
   Sensor reset pin RESETB is active low.
   AVDD is 2.8V sensor analog power.
   DVDD is 1.3V sensor digital power.
   DOVDD is 1.8V to 3.0V sensor digital IO power.
   Sensor AGND and DGND should be separated and connect to a
   single point at outside PCB (Don't connect inside module).
   C2 should close to sensor DVDD and DGND.
   C3 should close to sensor SVDD, AVDD and AGND.
   C4 should close to sensor VHRFH and AGND.
   C5 should close to sensor VREFN and AGND.
   C6 should close to sensor DOVDD and DGND.
   C1 should close to sensor EVDD and DGND.
   D9:D2 is module YUV and RGB 8bits output (D9:MSB, D2:LSB).
   D9:D0 is module raw RGB 10 bits output (D9:MSB, D0:LSB

2. OV2640 Camera Interface Reference for Camera Phone 

2.1 Pin Definition
OV2640 has 10-bit video port, D[9:0]. For 10-bit RGB raw output, D[9:0] are used. For 8-bit
YCbCr, 8-bit RGB raw or 8-bit RGB 565 output, only D[9:2] are used.
The Href and Hsync signal is on the same pin – Href pin. The function of this pin could be
selected as either Href function or Hsync function by SCCB setting.
The SIO_C and SIO_D bus should have external pull up resistors, the typical value of the pull up
resistors is about 4.7K.
Resetb is active low. There is no internal pull-down/pull-up resistor. It can be controlled by a
GPIO, or connected to DOVDD using an external pull-up resistor if not used. If Resetb is connected
to DOVDD, the OV2640 camera module could be reset by SCCB setting.
PWDN is active high. There is no internal pull-down/pull-up resistor. It can be controlled by a
GPIO, or connected to DGND using an external pull-down resistor if not used.
2.2 Power Supply
If DOVDD uses different power supply than AVDD, then 3 regulators should be used.

3. OV2640 Camera Operation 

3.1 Power Saving Modes
There are 2 kind of power saving modes: power down mode and power off mode.
Power down mode means that in power saving mode, all the power supplies to the camera
module are kept. The camera is set into power down mode by pull high PWDN. For OV2640,
there have big power down current, so power down mode is not supported by OV2640 for
power saving. But power down mode is still useful if OV2640 shares SCCB bus with other devices
or OV2640 shares video bus with another camera for camera applications. So OV2640 power
operation in power down mode is still introduced here.
Power off mode means that in power saving mode, all the power supplies to the camera module
are cut. 

3.2 Camera Operation in Power Down Mode 

3.2.1 Battery On, Hardware Reset
t1: from powers on to Reset pull high, >= 3ms
t2: from Reset pull high to SCCB initialization, >= 3ms
Step 1:
Reset is applied to OV2640 camera module.
Step 2:
DOVDD, DVDD and AVDD powers are applied. The 3 powers could be applied simultaneously.
If applied separately, the power on sequence should be DOVDD first, DVDD second and AVDD
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OV2640 Camera Module Hardware Application Notes
last.
Step 3:
after 3ms of last power applied, pull high Reset.
Step 4:
After 3ms, initialize OV2640 by SCCB initialization. Please find initialization setting from
“OV2640 Camera Module Software Application Notes” or contact OmniVision local FAE.
Step 5:
Pull high PWDN. Set OV2640 to power down mode.
Step 6:
Pull XCLK low.
After battery on, OV2640 cameras should be set to power down mode to minimize power
consumption. The cameras should be initialized first, then set to power down mode.

 3.2.2 Battery On, Software Reset
t1: from powers on to SCCB software reset, >= 3ms
t2: from software reset to SCCB initialization, >= 2ms
Step 1:
DOVDD, DVDD and AVDD powers are applied. The 3 powers could be applied simultaneously.
If applied separately, the power on sequence should be DOVDD first, DVDD second and AVDD
last.
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OV2640 Camera Module Hardware Application Notes
Step 2:
after 3ms of last power applied, reset OV2640 camera module by SCCB write.
Step 3:
After 2ms, initialize OV2640 by SCCB initialization. Please find the initialization setting from
“OV2640 Camera Module Software Application Notes” or contact OmniVision local FAE.
Step 4:
Pull high PWDN. Set OV2640 to power down mode.
Step 6:
Pull low XCLK.
3.2.3 Wake up From Power Down
Step 1:
Apply XCLK
Step 2:
after 10ms, Pull Low PWDN
Step 3:
Optional Step 4:
Initialization.
3.2.4 Power Down
Step 1:
Pull PWDN pin high.
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PWDN
SIO_C
SIO_D
XCLK
PWDN
SIO_C
SIO_D
XCLK
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OV2640 Camera Module Hardware Application Notes
Step 2:
Pull XCLK low 

3.3 Camera Operation in Power Off Mode

 3.3.1 Battery On
No operation. Camera module is power off. 

3.3.2 Camera On, Hardware Reset
t1: from powers on to SCCB software reset, >= 3ms
t2: from software reset to SCCB initialization, >= 2ms
Step

 1:
Reset is applied to OV2640 Camera Module.
Step 

2:
DOVDD, DVDD and AVDD powers are applied. The 3 powers could be applied simultaneously.
If applied separately, the power on sequence should be DOVDD first, DVDD second and AVDD
last.
Step 

3:
after 3ms of last power applied, pull high Reset.
Step 5:
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OV2640 Camera Module Hardware Application Notes
After 3ms, initialize OV2640 by SCCB initialization. Please find initialization setting from
“OV2640 Camera Module Software Application Notes”or contact OmniVision local FAE.
3.3.3 Camera On, Software Reset
t1: from powers on to SCCB software reset, >= 3ms
t2: from software reset to SCCB initialization, >= 2ms
Step 1:
DOVDD, DVDD and AVDD powers are applied. The 3 powers could be applied simultaneously.
If applied separately, the power on sequence should be DOVDD first, DVDD second and AVDD
last.
Step 2:
after 3ms of last power applied, reset OV2640 camera module by SCCB write.
Step 3:
After 2ms, initialize OV2640 by SCCB initialization. Please find initialization setting from
“OV2640 Camera Module Software Application Notes” or contact with OmniVision local FAE.
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OV2640 Camera Module Hardware Application Notes
3.3.4 Camera Off
Step 1.
Pull low XCLK,
Step 2.
Turn off AVDD, DVDD and DOVDD. The 3 powers could be turned off simultaneously. If
turned off separately, AVDD should be turned off first, DVDD second and DOVDD third.
Step 3.
Pull Low PWDN and RESET
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DOVDD
DVDD
AVDD
XCLK
Reset
PWDN
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OV2640 Camera Module Hardware Application Notes
4. SCCB Bus sharing
The SCCB bus of OV2640 camera module could share with other SCCB device. When OV2640
is working, the read/write operation is separated by device address. The device address of OV2640
is 0x60. SCCB read/write to address other than the 2 address above will not affect SCCB registers
of OV2640.
The SCCB bus of OV2640 could be shared with other devices in both power down mode and
power off mode. When OV2640 camera module is power down or power off, the SCCB Bus is
leave free. The SCCB of OV2640 doesn't affect the read/write of other SCCB device.

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