OV2640 Camera Module Hardware Application Notes1.04
OV2640 Camera Module Hardware Application Notes
Last Modified: Dec 12th , 2007Document Revision: 1.04
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.
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Table of Contents
1. OV2640 Camera Module Reference Design....................................................................................32. OV2640 Camera Interface Reference for Camera Phone................................................................42.1 Pin Definition.............................................................................................................................42.2 Power Supply.............................................................................................................................43. OV2640 Camera Operation..............................................................................................................63.1 Power Saving Modes.................................................................................................................63.2 Camera Operation in Power Down Mode..................................................................................63.2.1 Battery On, Hardware Reset..............................................................................................63.2.2 Battery On, Software Reset................................................................................................73.2.3 Wake up From Power Down..............................................................................................83.2.4 Power Down.......................................................................................................................83.3 Camera Operation in Power Off Mode......................................................................................93.3.1 Battery On..........................................................................................................................93.3.2 Camera On, Hardware Reset..............................................................................................93.3.3 Camera On, Software Reset.............................................................................................103.3.4 Camera Off.......................................................................................................................114. SCCB Bus sharing..........................................................................................................................125. Timing Considerations for Phone PCB Design..............................................................................135.1 Sample with PCLK..................................................................................................................135.2 Sample with XCLK.................................................................................................................145.3 Using EMI/ESD Device...........................................................................................................146. Hardware Check List......................................................................................................................156.1 Check Hardware Design..........................................................................................................156.1.1 Module Function..............................................................................................................156.1.2 Check Camera Interface of Phone....................................................................................156.2 Check if Camera Module is Working......................................................................................156.3 Check SCCB............................................................................................................................166.4 Check Camera Interface...........................................................................................................166.5 Some Typical Issues................................................................................................................176.6 Image Direction.......................................................................................................................186.6.1 Sensor 4:3, LCD 3:4.........................................................................................................186.6.2 Sensor 3:4, LCD 3:4.........................................................................................................186.7 Check Color/Brightness...........................................................................................................186.8 Check Image Center.. (19)
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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
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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.
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If DOVDD uses the same voltage as AVDD, then only 2 regulators are required. R/C filter is used to separate AVDD from DOVDD.
Please note that:
a. The AGND and DGND should be separate inside module and connected together on phone PCB very close to camera module connector.
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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 O
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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.O
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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.PWDN SIO_C SIO_D
XCLK
PWDN SIO_C
SIO_D
XCLK
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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:O
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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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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
DOVDD
DVDD
AVDD
XCLK Reset
PWDN
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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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5. Timing Considerations for Phone PCB Design
There are 2 clock signal for OV2640 camera module. One is the main clock (input clock) XCLK, the other is the pixel clock (output clock) PCLK. Some backend/baseband chips may use XCLK as pixel sample clock, some backend/baseband chips may use PCLK as pixel sample clock. It is recommended to use PCLK as pixel sample clock. Let's look at the clock distribution first.
So the delay of video data to clock at backend/baseband side is very critical for timing design. If the delay is over the spec. of backend/baseband chip, the backend/baseband chip can not get video data correctly. The incorrect video data may have wrong color, fixed or moving horizontal lines.
From the clock distribution diagram above, the delays are:
Delay_XCLK = 0
Delay_PCLK = PCB_Delay_XCLK + Internal_Delay + PLL_Delay + PCB_Delay_PCLK
Delay_Data = PCB_Delay_XCLK + Internal_Delay + PLL_Delay + PCLK_to_Data_Delay + PCB_Delay_Data
5.1 Sample with PCLK
If Backend/baseband sample video data with PCLK, the clock data delay is clock_data_delay = Delay_Data – Delay_PCLK
= PCLK_to_Data_Delay + PCB_Delay_Data – PCB_Delay_PCLK
The clock data delay is not related with PCB delay of XCLK.
If PCB is carefully designed so that the wire length of PCLK and Data are same, then PCB_Delay_Data = PCB_Delay_PCLK, the clock data delay is clock_data_delay = PCLK_to_Data_Delay, not related to PCB layout
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5.2 Sample with XCLK
If Backend/baseband sample video data with PCLK, the clock data delay is clock_data_delay = Delay_Data – Delay_XCLK
= PCB_Delay_XCLK + Internal_Delay + PLL_Delay + PCLK_to_Data_Delay + PCB_Delay_Data
The data to clock delay at Baseband/Backend chip are much bigger than sampled with PCLK.
And the delay is highly depend on PCB layout. So if XCLK is used to sample video data, it is very likely to have timing issue which would cause incorrect video data.
5.3 Using EMI/ESD Device
If EMI/ESD device are used in phone design, the PCB delay increase very much. It should be very careful to manipulate the delays to meet timing spec. of backend/baseband chips.1.Try to use PCLK as sample clock of video data.
2.XCLK and PCLK should not share ESD/EMI device with other signals. Use dedicate ESD/EMI device or R/C filters for XCLK and PCLK. So that the delay on XCLK and PCLK could be adjusted later.
3.For camera module, use single ESD/EMI device or single R/C filter for XCLK and PCLK to minimize clock delay.
4.Carefully layout PCB to keep XCLK wire as short as possible, PCLK wire the same length as data lines.
5.Minimize the length of FPC of camera module.
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6. Hardware Check List
6.1 Check Hardware Design 6.1.1 Module Function
Check camera module function with USB 2.0 test board (Module interface board may be needed, please contact with module maker). The module should display image correctly on PC.
Check module schematic design, pin definition match with camera interface of phone. Analog ground and digital ground are separated inside camera module.
6.1.2 Check Camera Interface of Phone
Pin definition matches with camera module design.
AVDD is supplied by separate regulator. DVDD and DOVDD could be supplied by separate regulator or shared regulator with other circuits. The voltage of each power supplied are within sensor specification.
If there is a long flex cable to connect camera module to main board of phone, please make sure the ground of camera module is not shared with other circuits. For flip type phone, share camera ground with LCD module would cause very strong power/ground noise.
6.2 Check if Camera Module is Working
Evidence of camera module working
PCLK output HREF, VSYNC outputs
D[9:0] output Check procedures
a. Voltages of power supplies are within sensor specification
b. input clock is correct
c. all input signals are in correct state
PWDN = in active, Reset = in active, SIO_D = H, SIO_C = H
d. for OV2640 and later, please check SCCB initialization waveform to make sure SCCB initialization is completed.
If all the check are passed, the camera module still can not work, please check if the camera module is damaged or contact OmniVision local FAE.
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6.3 Check SCCB
a. Check SCCB connection: Pull up resistors exist. Recommended value is around 4.7K.
b. SCCB write speed should not be too fast for first debug. Recommended not over 100K. The write speed could be increased up to 400K later on.
c. Simple ways to check SCCB
SCCB read could be verified by read register 0x0a, 0x0b (version).
SCCB write could be verified by write register 0x11 and check PCLK frequency.
d. To make sure SCCB read/write are correct, please use oscilloscope to capture whole waveforms of SCCB initialization.
e. Make sure the SCCB device ID is correct for read/write operation.
SCCB address is 0x60/0x61 for 1.3M and above sensors
f. If SCCB soft reset is used, please wait at least 2~5ms after SCCB soft rest.
6.4 Check Camera Interface
a. Check polarity of HREF(HSYCN), VSYNC, PCLK, make sure the polarity of camera module matches with backend or baseband side.
b. Check sample clock. Please pay attention to baseband/backend sample with MCLK. In this case, the clock divider inside sensor could not be turned on. Please also pay attention to possible timing issues listed in section 5.
c. check window position.
If camera interface uses HREF, then the window position is defined by sensor.
If camera interface uses HSYNC, then the window position is defined by backend / baseband.
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6.5 Some Typical Issues
Line width too big
In sufficient output lines
Line width too small
Wrong Window Position
Horizontal Sync Issue Vertical Sync Issue Sample Rate
too High
Sample rate too
low
Timing Issue
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6.6 Image Direction 6.6.1 Sensor 4:3, LCD 3:4
Full screen display is not full view angle Full view angle display is not full screen
Full view angle Full Screen
Camera module
6.6.2 Sensor 3:4, LCD 3:4
Sensor rotate 90 degree in camera module Picture scan line direction should be changed by phone
Full Screen and Full view angle on LCD
Full view angle & Full Screen
Change scan line direction of camera
6.7 Check Color/Brightness
a. There are only red/green color in picture
Y and U/V exchanged.b. R/B exchange
U/V exchange
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c. color/brightness not continuous
check connection of d[9:0]
6.8 Check Image Center
Place an object in front of camera module, check if the picture is on center of LCD. If not, the output window of camera is not correct.
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STC89C52单片机详细介绍
STC89C52是一种带8K字节闪烁可编程可檫除只读存储器（FPEROM-Flash Programable and Erasable Read Only Memory ）的低电压，高性能COMOS8的微处理器，俗称单片机。该器件采用ATMEL 搞密度非易失存储器制造技术制造，与工业标准的MCS-51指令集和输出管脚相兼容。 单片机总控制电路如下图4—1： 图4—1单片机总控制电路 1.时钟电路 STC89C52内部有一个用于构成振荡器的高增益反相放大器，引
脚RXD和TXD分别是此放大器的输入端和输出端。时钟可以由内部方式产生或外部方式产生。内部方式的时钟电路如图4—2(a) 所示，在RXD和TXD引脚上外接定时元件，内部振荡器就产生自激振荡。定时元件通常采用石英晶体和电容组成的并联谐振回路。晶体振荡频率可以在1.2～12MHz之间选择，电容值在5～30pF之间选择，电容值的大小可对频率起微调的作用。 外部方式的时钟电路如图4—2（b）所示，RXD接地，TXD接外部振荡器。对外部振荡信号无特殊要求，只要求保证脉冲宽度，一般采用频率低于12MHz的方波信号。片内时钟发生器把振荡频率两分频，产生一个两相时钟P1和P2，供单片机使用。 示，RXD接地，TXD接外部振荡器。对外部振荡信号无特殊要求，只要求保证脉冲宽度，一般采用频率低于12MHz的方波信号。片内时钟发生器把振荡频率两分频，产生一个两相时钟P1和P2，供单片机使用。 RXD接地，TXD接外部振荡器。对外部振荡信号无特殊要求，只要求保证脉冲宽度，一般采用频率低于12MHz的方波信号。片内时钟发生器把振荡频率两分频，产生一个两相时钟P1和P2，供单片机使用。
中考英语单词拼写专项训练
中考英语单词拼写专项训练 1.They eat a lot of _________(土豆). 2. Indiren can speak English well. But she is an __________(意大利人). 3. Would you like something __________(别的)? 4. Walk along the road and turn right at the third __________(十字路口). 5. It' s about five _________(天) work. 6. Do you think it _________(必需的) for us to learn to wait? 7. A few minutes __________(后), I saw the plane again. 8. It's not a very good line. Could you speak more _________(清楚) ? 9. Bob is no __________(不再) a young man. 10. The Green family __________(归来) to China last Friday. 11. You must stop _________(抽烟). 12. Hangzhou is one of the most beautiful __________(城市) in the world. 13. Have you visited my ____________(工作场所)? 14. Go to school _________(穿着) your school clothes on Monday. 15. They can't __________(带) the baby with them to go swimming. 16. There are some ____________(桥) over the river. 17. That old man __________(死) five weeks ago. 18. Father looks very _________(担忧的) today. 19. Be careful when you ___________(横穿) the busy street. 20. I didn't have bread for breakfast, I had a bowl of porridge ________(代替). 21. His father's coming back ________(使得) him feel very happy. 22. Today I came to school ___________(没有) breakfast. 23. I was too busy and ___________(错过) the film "Titanic". 24. I will tell you when he __________(到达) my home. 25. Is the license in one of your __________(衣服口袋) ? 26. --What's wrong? --I ___________(割) one of my fingers just now. 27. If someone ___________(推) hard, the old man will fall over. 28. There are so many ___________(参观者) in the West Lake. 29. You must keep __________(安静) in class. 30. He __________(改变) his name when he was in the USA. 31. It's not good to laugh at others' ___________(错误). 32. There's nothing ____________(严重) with him, I think. 33. The food smells very _____________(好). 34, Of the three, Mr Brown is the _____________(胖). 35. Do you __________(相信) what he said? 36. ___________(或许) he will come here tomorrow. 37. Can you make the baby stop ___________(哭) ? 38. The film is really __________(精彩). 39. I ___________(梦) I was in Shanghai last night. 40. Her dog died last week, her cat died today, it made her very __________(悲伤) 41. Mike ____________(跌倒) off the chair and hurt his leg. 42. It's hard ___________(完成) the work in such a short time. 43．The big boy ___________(叫做) Wu Hai is the best player on his team. 44. Mary enjoys ____________(听) to the music. 45. This is a black cat ______________(有) one white ear and two white legs. 46. My mother _________(担忧)about my health and study very much. 47. The twins enjoyed ________(她们自己) at the party. 48. Her __________(最喜欢的) subjects at school are science and maths. 49. This is an __________(有趣) story book for children. 50. Please drive more _________(仔细). 51. All the _________(跑步者) got ready to run. 52. The teacher stood at the ___________(起跑线) line. 53. The boat is __________(不见了), where is it? 54. Which sports were you ____________(参加) that day? 55. Which is ___________(难), English or Chinese? 56. Lucy did ____________(坏) than Lily in Chinese. 57. To our _________(惊奇), the old man's hair turned black the next day. 58. If you have a lot of ___________(钱), what will you do? 59. Here is __________(另一张) picture of mine. 60. He ________(听见) someone playing the piano last night. 61. The old woman couldn't find her purse, she looked ________(着急). 62. We _______(举行) an English party the day before yesterday. 63. The baby laughed ________(高兴). 64. If it __________(下雨) tomorrow, we won' t go to the zoo. 65. An __________(印度人) showed them the way on the map. 66. Is his father a _________(厨师)or a cleaner? 67. I don't ________(真正地) agree with you. 68. It _________(好象) that Chinese food is very popular in the world. 69. He likes the _________(汤) with popper and oil. 70. She is a good _______(善良的) girl. 71. Don't _______(横穿) the road. It is dangerous. 72. There aren't any ___________(迹象) along the mad. He is lost. 73. That car nearly ________(撞) her. 74. There are many ________(旅客) at the bus station. 75. Don't make any ________(吵闹). You'll wake the baby up. 76. She is studying. You mustn't __________(打扰) her. 77. I often feel weak and _______(疲劳). 78. Waikiki is one of the best beaches for _______(冲浪) in Honolulu. 79. I hope someday diving will be an __________(比赛项目) of the Olympic Games. 80. --Are you doing OK in _________(保护) the environment? --Yes. 第1 页共3 页
标准物质与标准样品
1 概述 在国际上标准物质和标准样品英文名称均为“Reference Materials”，由 ISO/REMCO组织负责这一工作。在我国计量系统将“Reference Materials”叫为“标准物质”，而标准化系统叫为“标准样品”。实际上二者有很多相同之处，同时也有一些微小差异（见表1）。 2 标准物质的分类与分级 2.1 标准物质的分类 根据中华人民共和国计量法的子法—标准物质管理办法（1987年7月10日国家计量局发布）中第二条之规定：用于统一量值的标准物质，包括化学成分标准物质、物理特性与物理化学特性测量标准物质和工程技术特性测量标准物质。按其标准物质的属性和应用领域可分成十三大类，即：
l 钢铁成分分析标准物质； l 有色金属及金属中气体成分分析标准物质； l 建材成分分析标准物质； l 核材料成分分析与放射性测量标准物质； l 高分子材料特性测量标准物质； l 化工产品成分分析标准物质； l 地质矿产成分分析标准物质； l 环境化学分析标准物质； l 临床化学分析与药品成分分析标准物质； l 食品成分分析标准物质； l 煤炭石油成分分析和物理特性测量标准物质； l 工程技术特性测量标准物质； l 物理特性与物理化学特性测量标准物质。 2.2 标准物质的分级 我国将标准物质分为一级与二级，它们都符合“有证标准物质”的定义。 2.2.1 一级标准物质 一级标准物质是用绝对测量法或两种以上不同原理的准确可靠的方法定值，若只有一种定值方法可采取多个实验室合作定值。它的不确定度具有国内最高水平，均匀性良好，在不确定度范围之内，并且稳定性在一年以上，具有符合标准物质技术规范要求的包装形式。一级标准物质由国务院计量行政部门批准、颁布并授权生产，它的代号是以国家级标准物质的汉语拼音中“Guo”“Biao”“Wu”三个字的字头“GBW”表示。 2.2.2 二级标准物质 二级标准物质是用与一级标准物质进行比较测量的方法或一级标准物质的定值方
关于国内工程保理业务介绍
关于国内工程保理业务介绍 根据我行最新国内保理业务管理办法，现将本业务作如下介绍： 一、本业务涉及到的几个定义 （一）国内保理业务是指境内卖方将其向境内买方销售货物或提供服务所产生的应收账款转让给我行，由我行为卖方提供应收账款管理、保理融资及为买方提供信用风险担保的综合性金融业务。其中，我行为卖方提供的应收账款管理和保理融资服务为卖方保理，为买方提供的信用风险担保服务为买方保理。 工程保理是指工程承包商或施工方将从事工程建设服务形成 的应收账款转让给卖方保理行，由保理行提供综合性保理服务。（二）卖方（供应商、债权人）：对所提供的货物或服务出具发票 的当事方，即保理业务的申请人。 （三）买方（采购商、债务人）：对由提供货物或服务所产生的应 收账款负有付款责任的当事方。 （四）应收账款：本办法所称应收账款指卖方或权利人因提供货物、服务或设施而获得的要求买方或义务人付款的权利，包括现有的金钱债权及其产生的收益，包括但不限于应收账款本金、利息、违约金、损害赔偿金，以及担保权利、保险权益等所有主债权、从债权以及与主债权相关的其他权益，但不包括因票据或其他有价证券而产生的付款请求权。 （四）应收账款发票实有金额：是指发票金额扣除销售方已回笼货款后的余额。
（五）保理监管专户：指卖方保理行为卖方开立的用于办理保理项下应收账款收支业务的专用账户。该账户用途包括：收取保理项下应收账款；收取其他用以归还我行保理融资的款项；支付超过保理融资余额以外的应收账款等。卖方不能通过应收账款专户以网上银行或自助设备等形式开展任何业务。 二、保理业务分类 （一）按是否对保理融资具有追索权，我行国内保理分为有追索权保理和无追索权保理。 有追索权保理是指卖方保理行向卖方提供保理项下融资后，若买方在约定期限内不能足额偿付应收账款，卖方保理行有权按照合同约定向卖方追索未偿还融资款的保理业务；无追索权保理是指卖方保理行向卖方提供保理项下融资后，若买方因财务或资信原因在约定期限内不能足额偿付应收账款，卖方保理行无权向卖方追索未偿还融资款。 三、应收账款的范围、条件及转让方式 (一）可办理国内保理业务的应收账款范围： 1、因向企事业法人销售商品、提供服务、设施而形成的应收 账款； 2、由地市级（含）以上政府的采购部门统一组织的政府采购 行为而形成的应收账款； 3、由军队军级（含）以上单位的采购部门统一组织的军队采 购行为而形成的应收账款；
(完整版)九年级英语单词拼写专项练习
九年级英语单词拼写 1、读句子，根据所给汉语或首字母提示写出单词。 86. Tom is such an honest and ____________ (乐于助人的) boy that all the neighbors like him. 87. You can not ____________ (想象) how knowledgeable the person is. 88. Just now we did an ____________ (实验) in the laboratory. 89. As a teacher, you should be ____________ (耐心的) 1o your students. 90. There are seven continents (大洲) and four o____________ in the world. 2、根据括号中所给的汉语写出单词，使句子意思完整正确。 1. Many topics are ____________ (涉及) in the report, including travelling and weather. 2. A lot of ________ (研究) on the change of the climate has been done. 3. His __________ (精神) of kindness will be remembered for ever. 4. Yao Ming is an ___________ (优秀的) basketball player. 5. A friend in need is a friend ________ (真正地). B: 用括号内所给单词的适当形式填空。 6. After they discussed for 2 hours, they came to an _________ (agree) at last. 7. His son has come to China for _________ (far) study. 8. John felt _________ (happiness) because he didn’t pass the driving test. 9. The more books you read, the more ___________ (know) you will get. 10. Nothing is ___________ (possible) if you put your heart into it. 3、根据所给中文正确拼写单词,每空限填一词。 66. If you are the ___________ (赢家), you will get the prize of 5000 yuan.
国际标准物质介绍
一、NIST标准物质： 1.资源介绍 美国NIST是世界上开展标准物质研制最早的机构。NIST的前身为美国国家标准局，成立于1901年，是设在美国商务部科技管理局下的非管理机构，负责国家层面上的计量基础研究。NIST在研究权威化学及物理测量技术的同时，还提供以NIST为商标的各类标准参考物质（SRM，Standard Reference Material），该商标以使用权威测量方法和技术而闻名。目前，NIST共提供1300多种标准参考物质，形成了世界领先的、较为完善的标准物质体系，在保证美国国内化学测量量值的有效溯源及分析测量结果的可靠性方面发挥了重要的支撑作用。总体来讲，美国NIST与其它美国商业标准物质生产者的关系是：NIST作为国家计量院将其研究重点放在高端标准物质及测量标准的研究上，建立国家的高端量值溯源体系，商业标准物质将其量值通过NTRM、校准等各种形式溯源至NIST，以改善标准物质的供应状况，满足不同层次用户对标准物质日益增长的需求。 NIST在采纳由ISO制定的国际计量学通用基本术语中对CRM、RM的定义外，又将其标准物质分为SRM（标准参考物质）、RM（标准物质）及NTRM（可溯源至NIST的标准物质）。对它们分别解释如下： NIST SRM：符合NIST规定的附加定值准则，带有证书（物理特性类）或分析证书（化学成分类）并在证书上提供其定值结果及相关使用信息的有证标准物质（CRM）。该类标准物质必须含有认定值（Certified value），同时可提供参考值和信息值； NIST RM：由NIST发布的、带有研究报告而不是证书的标准物质。该类标准物质除了符合ISO对RM的定义，还可能符合ISO对CRM的定义。该类标准物质必须含有参考值，同时可提供信息值； NTRM：可以通过很好建立的溯源链溯源至NIST化学测量标准的商业标准物质。溯源链的建立必须符合由NIST确定的系列标准和草案。通过管理授权，NTRM也可等价于CRM。NTRM模式目前在气体分析用标准物质和光度分析用标准物质方面得到了很好的应用； 在标准物质所提供的特性量值方面，有以下三类： NIST认定值：具有最高准确度、所有已知或可疑偏差来源均已经过充分研究或
STC89C52单片机用户手册
STC89C52RC单片机介绍 STC89C52RC单片机是宏晶科技推出的新一代高速/低功耗/超强抗干扰的单片机，指令代码完全兼容传统8051单片机，12时钟/机器周期和6时钟/机器周期可以任意选择。 主要特性如下： 增强型8051单片机，6时钟/机器周期和12时钟/机器周期可以任意选择，指令代码完全兼容传统8051. 工作电压：～（5V单片机）/～（3V单片机） 工作频率范围：0～40MHz，相当于普通8051的0～80MHz，实际工作频率可达48MHz 用户应用程序空间为8K字节 片上集成512字节RAM 通用I/O口（32个），复位后为：P1/P2/P3/P4是准双向口/弱上拉，P0口是漏极开路输出，作为总线扩展用时，不用加上拉电阻，作为 I/O口用时，需加上拉电阻。 ISP（在系统可编程）/IAP（在应用可编程），无需专用编程器，无需专用仿真器，可通过串口（RxD/,TxD/）直接下载用户程序，数秒 即可完成一片 具有EEPROM功能 具有看门狗功能 共3个16位定时器/计数器。即定时器T0、T1、T2 外部中断4路，下降沿中断或低电平触发电路，Power Down模式可由外部中断低电平触发中断方式唤醒 通用异步串行口（UART），还可用定时器软件实现多个UART 工作温度范围：-40～+85℃（工业级）/0～75℃（商业级） PDIP封装 STC89C52RC单片机的工作模式 掉电模式：典型功耗<μA,可由外部中断唤醒，中断返回后，继续执行
原程序 空闲模式：典型功耗2mA 正常工作模式：典型功耗4Ma～7mA 掉电模式可由外部中断唤醒，适用于水表、气表等电池供电系统及便携设备 STC89C52RC引脚图 STC89C52RC引脚功能说明 VCC（40引脚）：电源电压 VSS（20引脚）：接地 P0端口（～，39～32引脚）：P0口是一个漏极开路的8位双向I/O口。作为输出端口，每个引脚能驱动8个TTL负载，对端口P0写入“1”时，可以作为高阻抗输入。
2017年中考英语专题练习《单词拼写》真题附完整答案
2017年中考英语专题练习《单词拼写》 (一)(2016·常州) 1. Every year, (百万)of people donate money to the Hope Project. 2. I will be happy if Sandy (接受)my offer. 3. I've never (后悔)the decision to work in WestChina. 4. He has a special (能力)to write with two hands at the same time. (二)(2016·南京) 1.一I find the game without Kobe Bryant boring. 一I don't agree. One player cannot make a (队). 2. There is an (空的)bottle on the road. Everyone should be careful. 3. It's a good idea to give your father a (夹克衫)as a gift on June 19, Father's Day. 4.一Where shall we go for the summer outing, Daniel? 一I can't (记得)exactly, maybe somewhere near Babulo Valley. 5. If everyone thinks about pollution and recycling, we can protect the air and help (救)our world. (三)(2016·济宁) 1. Please keep (安静)when you are in a library. 2. Do you need to (讨论)the problem in groups? 3. Students should answer questions loudly and (清楚地)in class. 4. Jack looked through the (介绍)about the book before he decided to buy it. (四)(2016·青岛) 1. In the USA, people eat with (刀) and forks. 2. I left my book at home. May I borrow (你的)? 3. You must look at the traffic lights before you go (穿过)the road. 4. It rained (大)on my way home yesterday of ternoon. 5. The (越早)kids learn to be independent, the better it is for their future. (五)(2016·无锡) 1. Be polite, Henry. It's rude to (指向)at others like that. 2. Reading is important, for it can open up an (未知的)world to us. 3. To my surprise, the 3-year-old boy can spell all those words (正确地). 4. Sue always has great (勇气)to face difficulties and that's why we all respect her. (六)(2016·连云港) 1.一Come on, Sandy. Everybody will be lucky or (成功的)sometime in their life. 一Thanks, I'll try again. 2. Flight 846 (降落)safely ten minutes ago with 300 passengers. 3.Researchers say temperatures in North Africa will continue (上升)this summer. 4. On his way back home, Frank lost his wallet because of his (粗心). (七)(2016·阜康、米泉) 1. After you argue with your parents you must (交流)with them and explain why you did that.
标准物质GBWGBWEBWGSB的区别
标准物质GBW、GBW（E）、BW、GSB的区别 1 概述 在国际上标准物质和标准样品英文名称均为“Reference Materials”，由 ISO/REMCO组织负责这一工作。在我国计量系统将“Reference Materials”叫为“标准物质”，而标准化系统叫为“标准样品”。实际上二者有很多相同之处，同时也有一些微小差异（见表1）。 CAS号（CAS Registry Number或称CAS Number, CAS Rn, CAS #），又称CAS登录号，是某种物质（化合物、高分子材料、生物序列（Biological sequences）、混合物或合金）的唯一的数字识别号码。美国化学会的下设组织化学文摘服务社 （Chemical Abstracts Service, CAS）负责为每一种出现在文献中的物质分配一个CAS号，其目的是为了避免化学物质有多种名称的麻烦，使数据库的检索更为方便。 2 标准物质的分类与分级 2.1 标准物质的分类 根据中华人民共和国计量法的子法—标准物质管理办法（1987年7月10日国家计量局发布）中第二条之规定：用于统一量值的标准物质，包括化学成分标准物质、物理特性与物理化学特性测量标准物质和工程技术特性测量标准物质。按其标准物质的属性和应用领域可分成十三大类， 2.2 标准物质的分级 我国将标准物质分为一级与二级，它们都符合“有证标准物质”的定义。 2.2.1 一级标准物质
一级标准物质又称国家一级标准物质，是由国家权威机构审定的标准物质。例如，美国国家标准局的SRM标准物质，英国的BAS标准物质，联邦德国的BAM标准物质，我国的GBW标准物质等。一级标准物质一般用绝对测量法或其它准确可靠的方法确定物质的含量，准确定为本国最高水平。我国国家技术监督局规定的国家一级标准物质应具备的基本条件为：①用绝对测量法或两种以上不同原理的准确可靠的测量方法进行定值，也可由多个实验室用准确可靠的方法协作定值；②定值的准确度应具有国内最高水平；③应具有国家统一编号的标准物质证书；④稳定时间应在1年以上；⑤均匀性应保证在定值的精度范围内； ⑥具有规定的合格包装形式。一般说来，一级标准物质应具有0.3-1%的准确度。一级标准物质由国务院计量行政部门批准、颁布并授权生产，它的代号是以国家级标准物质的汉语拼音中“Guo”“Biao”“Wu”三个字的字头“GBW”表示。 2.2.2 二级标准物质 二级标准物质是用与一级标准物质进行比较测量的方法或一级标准物质的定值方法定值，其不确定度和均匀性未达到一级标准物质的水平，稳定性在半年以上，能满足一般测量的需要，包装形式符合标准物质技术规范的要求。二级标准物质由国务院计量行政部门批准、颁布并授权生产，它的代号是以国家级标准物质的汉语拼音中“Guo”“Biao”“Wu”三个字的字头“GBW”加上二级的汉语拼音中“Er”字的字头“E”并以小括号括起来――GBW（E）。 GBW和GBW（E）是总局批准的国家级标准物质，属于有证标准物质。BW是中国计量院学报标准物质，未通过总局批准，没有取得有证标准物质号. 2.3 标准物质的编号 一种标准物质对应一个编号。当该标准物质停止生产或停止使用时，该编号不再用于其他标准物质，该标准物质恢复生产和使用仍启用原编号。 准物质目录编辑顺序一致）。第三位数是标准物质的小类号，每大类标准物质分为1-9个小类。第四-五位是同一小类标准物质中按审批的时间先后顺序排列的顺序号。最后一位是标准物质的产生批号，用英文小写字母表示，排于标准物质编号的最后一位，生产的第一批标准物质用a表示，第二批用b表示，批号顺序与英文字母顺序一致。GBW07101a超基性岩，表示地质类中岩石小类第一个批准的标准物质，首批产品。 如：GBW02102b铁黄铜，表示有色金属类中铜合金小类第二个批准的标准物质，第二批产品。 2.3.2 二级标准物质 二级标准物质的编号是以二级标准物质代号“GBW（E）”冠于编号前部，编号的前两位数是标准物质的大类号，第三、四、五、六位数为该大类标准物质的顺序号。生产批号同一级标准物质生产批号，如GBW（E）110007a表示煤炭石油成分分析和物理特性测量标准物质类的第7顺序号，第一批生产的煤炭物理性质和化学成分分析标准物质。 2.4 标准物质的分类编号 标准物质的分类编号，见表2。
STC89C52RC单片机手册范本
STC89C52单片机用户手册 [键入作者姓名] [选取日期]
STC89C52RC单片机介绍 STC89C52RC单片机是宏晶科技推出的新一代高速/低功耗/超强抗干扰的单片机，指令代码完全兼容传统8051单片机，12时钟/机器周期和6时钟/机器周期可以任意选择。 主要特性如下： 1.增强型8051单片机，6时钟/机器周期和12时钟/机器周期可以任 意选择，指令代码完全兼容传统8051. 2.工作电压：5.5V～ 3.3V（5V单片机）/3.8V～2.0V（3V单片机） 3.工作频率范围：0～40MHz，相当于普通8051的0～80MHz，实 际工作频率可达48MHz 4.用户应用程序空间为8K字节 5.片上集成512字节RAM 6.通用I/O口（32个），复位后为：P1/P2/P3/P4是准双向口/弱上 拉，P0口是漏极开路输出，作为总线扩展用时，不用加上拉电阻， 作为I/O口用时，需加上拉电阻。 7.ISP（在系统可编程）/IAP（在应用可编程），无需专用编程器，无 需专用仿真器，可通过串口（RxD/P3.0,TxD/P3.1）直接下载用 户程序，数秒即可完成一片 8.具有EEPROM功能 9.具有看门狗功能 10.共3个16位定时器/计数器。即定时器T0、T1、T2 11.外部中断4路，下降沿中断或低电平触发电路，Power Down模式
可由外部中断低电平触发中断方式唤醒 12.通用异步串行口（UART），还可用定时器软件实现多个UART 13.工作温度范围：-40～+85℃（工业级）/0～75℃（商业级） 14.PDIP封装 STC89C52RC单片机的工作模式 ●掉电模式：典型功耗<0.1μA,可由外部中断唤醒，中断返回后，继续执行原 程序 ●空闲模式：典型功耗2mA ●正常工作模式：典型功耗4Ma～7mA ●掉电模式可由外部中断唤醒，适用于水表、气表等电池供电系统及便携设备
必修二单词拼写专项练习100题
第二模块单词拼写测试卷 Unit 1 1. Only two passengers s________ the air crash but they were badly injured. 2. Lucy is mild—it’s extremely r________ for her to lose her temper. 3. This book b________ to Sarah—I must give it back to her. 4. The building has been specially d________ to provide easy access for people in wheelchairs. 5. By the power of f________, we may create an unreal world. 6. I like the s________ of his writing but I don’t like the content. 7. Westerners usually d________ their houses for Christmas. 8. The expensive j________ are kept in the safe (保险箱). 9. Though they are in love for a long time, I d________ whether he has any intention of marrying her. 10. Mary r________ the painting to another wall the other day. 11. The e________ has given an account of the traffic accident. 12. This old vase dates from the Ming D________. 13. Our school gave a r________ to our new principal. 14. The car is waiting at the e________ to the school gate. 15. At last, they succeeded in the experiment on the fifteenth t________. 16. There is some e________ to suggest that he was there on the night of the murder. 17. After much d________, the committee voted to close the school. 18. The terrorists e________ a bomb in a restaurant in Pakistan three days ago. 19. The famous actor’s sudden disappearance was a complete m________. 20. He told me i________ that I’d got the job, but that official confirmation (确认) wouldn’t come until a few days later. Unit 2 1. The work cost us nothing; it’s all done by v________ from a university. 2. Michael Phelps won eight gold m________ in the 2008 Beijing Olympics. 3. London is the h________ city for the next Olympic Games. 4. The football game will be played at the capital s________. 5. Stress has an effect on both your p________ and mental health. 6. When we say one keeps r________ hours, that means he or she gets up and goes to bed at the same time each day. 7. P________ Anne is the prettiest one of all the daughters of the king. 8. Tom’s f________ behaviour made me think he was out of his senses. 9. The m________ of the Olympics is “Swifter, Higher, Stronger.” 10. The s________ between the two reports suggests that one person wrote both. 11. We were impressed by the ruins of an a________ building in Rome. 12. C________ among youths to enter the best colleges is intense (激烈的). 13. The fairy’s m________ changed the two brothers into ducks. 14. An a________ is a person who competes in sports such as running and jumping. 15. That second-hand table was a real b________ at only $ 6. 16. She a________ that she had stolen the bicycle. 17. Even if Lincoln was not ready to confess (承认) it, black people knew that this was a war against s________. 18. He r________ his brother as captain because his brother was ill. 19. The bad girl d________ to be punished—nobody took pity on her. 20. If you want to sell your products better, you had better a________ them.
STC89C52单片机学习开发板介绍
STC89C52单片机学习开发板介绍 全套配置： 1 .全新增强STC89C5 2 1个【RAM512字节比AT89S52多256个字节FLASH8K】 2 .优质USB数据线 1条【只需此线就能完成供电、通信、烧录程序、仿真等功能，简洁方便实验，不需要USB 转串口和串口线，所有电脑都适用】 3 .八位排线 4条【最多可带4个8*8 LED点阵，从而组合玩16*16的LED点阵】 4 .单P杜邦线 8条【方便接LED点阵等】 5 .红色短路帽 19个【已装在开发箱板上面，短路帽都是各功能的接口,方便取用】 6 .实验时钟电池座及电池 1PCS 7 .DVD光盘 1张【光盘具体内容请看页面下方，光盘资料截图】 8 .全新多功能折叠箱抗压抗摔经久耐磨 1个【市场没有卖,专用保护您爱板的折叠式箱子，所有配件都可以放入】 9 .8*8（红+绿）双色点阵模块 1片【可以玩各种各样的图片和文字,两种颜色变换显示】 10.全新真彩屏SD卡集成模块 1个【请注意：不包含SD卡，需要自己另外配】 晶振【1个方便您做实验用】 12.全新高速高矩进口步进电机 1个【价格元/个】 13.全新直流电机 1个【价值元/ 个】 14.全新红外接收头 1个【价格元/ 个】 15.全新红外遥控器（送纽扣电池） 1个【价格元/个】 16.全新18B20温度检测 1个【价格元/只】 17.光敏热敏模块 1个（已经集成在板子上）【新增功能】 液晶屏 1个 配件参照图：
温馨提示：四点关键介绍，这对您今后学习51是很有帮助的） 1.板子上各模块是否独立市场上现在很多实验板，绝大部分都没有采用模块化设计，所有的元器件密 密麻麻的挤在一块小板上，各个模块之间PCB布线连接，看上去不用接排线，方便了使用者，事实上是为了降低硬件成本，难以解决各个模块之间的互相干扰，除了自带的例程之外，几乎无法再做任何扩展，更谈不上自由组合发挥了，这样对于后继的学习非常不利。几年前的实验板，基本上都是这种结构的。可见这种设计是非常过时和陈旧的，有很多弊端，即便价格再便宜也不值得选购。 HC6800是采用最新设计理念，实验板各功能模块完全独立，互不干扰，功能模块之间用排线快速连接。 一方面可以锻炼动手能力，同时可加强初学者对实验板硬件的认识，熟悉电路，快速入门；另一方面，因为各功能模块均独立设计，将来大家学习到更高级的AVR，PIC，甚至ARM的时候，都只