2018.03.19 -编译器优化以及volatile

本文详细解析了C++中的volatile关键字,解释了何时及为何使用volatile来声明变量,以及它如何影响编译器对变量的优化。

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首先看一下单词“volatile”的释义:

volatile [ˈvɑlətl]

adj.  易变的,不稳定的; (液体或油)易挥发的; 爆炸性的; 快活的,轻快的;

下边是“C++ Primer”对volatile讲解的部分摘录:

“当一个对象的值可能会在编译器的控制或监测之外被改变时,该对象应该声明为volatile。因此,编译器执行的某些例行优化行为不能应用在已经指定为volatile的对象上……volatile修饰符的主要目的是提示编译器,该对象的值可能在编译器未监测到的情况下被改变。因此编译器不能武断地对引用这些对象的代码作优化处理。”

可见,修饰符volatile定义了一个“易变的、不稳定的、随时可能改变的”变量,对于被声明为volatile的变量的使用上跟普通的变量没有什么区别,最大的影响,就是编译器不能按照常规方式对其进行优化。

这就引入了两个问题:

编译器为何对访问变量的方式做优化以及如何优化?

编译器为何优化:

首先有这么个前提明确一下:编译器对变量的存取速度,寄存器快于内存,最慢是硬盘。

寄存器快于内存的主要原因体现在两者工作方式的差别上:

寄存器本身位于CPU内部,使用起来非常简单:第一,找到相关的位,第二,读取这些位,Over。

相比之下,内存的工作方式就复杂很多:

1.找到数据的指针指针可能存放在寄存器内,所以这一步就已经包括寄存器的全部工作了。

2.将指针送往内存管理单元(MMU),由MMU将虚拟的内存地址翻译成实际的物理地址。

3.将物理地址送往内存控制器(memory controller),由内存控制器找出该地址在哪一根内存插槽(bank)上。

4.确定数据在哪一个内存块(chunk)上,从该块读取数据。

5.数据先送回内存控制器,再送回CPU,然后开始使用。

相对复杂的工作流程产生了更多的时延,累计起来就比寄存器慢很多,为了提高执行效率,编译器会对有必要优化的变量做访问方式上的处理,这就是编译器对变量的优化。

如何优化:

多数情况下,变量是存放在内存而非寄存器中的,这样对变量的存取效率很低。对于频繁使用的变量,编译器自动地把变量mov到寄存器里,使用的时候直接访问寄存器里的值,以加快存取速度,这就是寄存器对变量的优化。

早期C编译程序时不会把变量保存在寄存器中,除非显示使用关键字register修饰变量:

[cpp]  view plain  copy
  1. register long int value=123456789;  

该关键字提醒编译器,所定义的变量会在程序中频繁被使用,建议编译器将其保存在CPU的寄存器中,以加快存取速度。其后随着编译技术的进步,编译器比程序员能更好的决定变量是应该存储在内存还是寄存器中,早在C++ 98/03标准中就明确,用register关键字声明的变量和不使用该关键字声明的变量一样,都具有自动存储期,现在在标准C++中,虽然还可以使用该关键字,但已经不再影响变量的实际定义。

对于被volatile 关键字修饰的变量,已经提前告知编译器该变量可能被某些编译器未知的因素更改,比如:操作系统、硬件或者其它线程等。遇到这个关键字声明的变量,编译器对访问该变量的代码就不再进行优化,从而可以提供对特殊地址的稳定访问,也就是说系统总是从它所在的内存地址读取数据,而非寄存器,并且使用完成之后立即按原路保存该变量的更改到内存。

volatile用法

volatile的用法跟关键字const用法一样
[cpp]  view plain  copy
  1. <pre name="code" class="cpp">volatile long clock_register;  
被volatile修饰的变量表示该变量会在意想不到的情况下改变,而const修饰的变量表示变量是不可改变的,那么一个变量能否同时使用volatile和const修饰呢?
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  1. volatile const long clock_register;  
[cpp]  view plain  copy
  1. const volatile long clock-register;  
答案是肯定的,一个例子是只读的 状态寄存器 ,用volatile修饰表示它可能会被意想不到的情况改变,这里是指编译器外部的情况,用const修饰表示在程序内部,不应该试图去人为修改它的值。
根据此代码修改:/* ArduCAM.h - Arduino library support for CMOS Image Sensor Copyright (C)2011-2015 ArduCAM.com. All right reserved Basic functionality of this library are based on the demo-code provided by ArduCAM.com. You can find the latest version of the library at http://www.ArduCAM.com Now supported controllers: - OV7670 - MT9D111 - OV7675 - OV2640 - OV3640 - OV5642 - OV5640 - OV7660 - OV7725 - MT9M112 - MT9V111 - OV5640 - MT9M001 - MT9T112 - MT9D112 We will add support for many other sensors in next release. Supported MCU platform - Theoretically support all Arduino families - Arduino UNO R3 (Tested) - Arduino MEGA2560 R3 (Tested) - Arduino Leonardo R3 (Tested) - Arduino Nano (Tested) - Arduino DUE (Tested) - Arduino Yun (Tested) - Raspberry Pi (Tested) - ESP8266-12 (Tested) * Feather M0 (Tested with OV5642) If you make any modifications or improvements to the code, I would appreciate that you share the code with me so that I might include it in the next release. I can be contacted through http://www.ArduCAM.com This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ /*------------------------------------ Revision History: 2012/09/20 V1.0.0 by Lee first release 2012/10/23 V1.0.1 by Lee Resolved some timing issue for the Read/Write Register 2012/11/29 V1.1.0 by Lee Add support for MT9D111 sensor 2012/12/13 V1.2.0 by Lee Add support for OV7675 sensor 2012/12/28 V1.3.0 by Lee Add support for OV2640,OV3640,OV5642 sensors 2013/02/26 V2.0.0 by Lee New Rev.B shield hardware, add support for FIFO control and support Mega1280/2560 boards 2013/05/28 V2.1.0 by Lee Add support all drawing functions derived from UTFT library 2013/08/24 V3.0.0 by Lee Support ArudCAM shield Rev.C hardware, features SPI interface and low power mode. Support almost all series of Arduino boards including DUE. 2014/03/09 V3.1.0 by Lee Add the more impressive example sketches. Optimise the OV5642 settings, improve image quality. Add live preview before JPEG capture. Add play back photos one by one after BMP capture. 2014/05/01 V3.1.1 by Lee Minor changes to add support Arduino IDE for linux distributions. 2014/09/30 V3.2.0 by Lee Improvement on OV5642 camera dirver. 2014/10/06 V3.3.0 by Lee Add OV7660,OV7725 camera support. 2015/02/27 V3.4.0 by Lee Add the support for Arduino Yun board, update the latest UTFT library for ArduCAM. 2015/06/09 V3.4.1 by Lee Minor changes and add some comments 2015/06/19 V3.4.2 by Lee Add support for MT9M112 camera. 2015/06/20 V3.4.3 by Lee Add support for MT9V111 camera. 2015/06/22 V3.4.4 by Lee Add support for OV5640 camera. 2015/06/22 V3.4.5 by Lee Add support for MT9M001 camera. 2015/08/05 V3.4.6 by Lee Add support for MT9T112 camera. 2015/08/08 V3.4.7 by Lee Add support for MT9D112 camera. 2015/09/20 V3.4.8 by Lee Add support for ESP8266 processor. 2016/02/03 V3.4.9 by Lee Add support for Arduino ZERO board. 2016/06/07 V3.5.0 by Lee Add support for OV5642_CAM_BIT_ROTATION_FIXED. 2016/06/14 V3.5.1 by Lee Add support for ArduCAM-Mini-5MP-Plus OV5640_CAM. 2016/09/29 V3.5.2 by Lee Optimize the OV5642 register settings 2016/10/05 V4.0.0 by Lee Add support for second generation of ArduCAM shield V2, ArduCAM-Mini-5MP-Plus(OV5642/OV5640). 2016/10/28 V4.0.1 by Lee Add support for Raspberry Pi 2017/04/27 V4.1.0 by Lee Add support for OV2640/OV5640/OV5642 functions. 2017/07/07 V4.1.0 by Lee Add support for ArduCAM_ESP32 paltform 2017/07/25 V4.1.1 by Lee Add support for MT9V034 2017/11/27 V4.1.2 by Max Add support for Feather M0 2018/10/15 V4.1.2 by Lee Add support for NRF52 2018/10/15 V4.1.2 by Lee Add support for TEENSYDUINO --------------------------------------*/ // 兼容性定义,放在 #include <ArduCAM.h> 之前或之后 #ifndef sbi #define sbi(port, bit) ((port) |= (1 << (bit))) #endif #ifndef ArduCAM_H #define ArduCAM_H #include "memorysaver.h" #if defined(RASPBERRY_PI) #else #include "Arduino.h" #include <pins_arduino.h> // #include "memorysaver.h" #endif #if defined(__AVR__) #define cbi(reg, bitmask) *reg &= ~bitmask #define sbi(reg, bitmask) *reg |= bitmask #define pulse_high(reg, bitmask) \ sbi(reg, bitmask); \ cbi(reg, bitmask); #define pulse_low(reg, bitmask) \ cbi(reg, bitmask); \ sbi(reg, bitmask); #define cport(port, data) port &= data #define sport(port, data) port |= data #define swap(type, i, j) \ { \ type t = i; \ i = j; \ j = t; \ } #define fontbyte(x) pgm_read_byte(&cfont.font[x]) #define regtype volatile uint8_t #define regsize uint8_t #endif #if defined(__SAM3X8E__) #define cbi(reg, bitmask) *reg &= ~bitmask #define sbi(reg, bitmask) *reg |= bitmask #define pulse_high(reg, bitmask) \ sbi(reg, bitmask); \ cbi(reg, bitmask); #define pulse_low(reg, bitmask) \ cbi(reg, bitmask); \ sbi(reg, bitmask); #define cport(port, data) port &= data #define sport(port, data) port |= data #define swap(type, i, j) \ { \ type t = i; \ i = j; \ j = t; \ } #define fontbyte(x) cfont.font[x] #define regtype volatile uint32_t #define regsize uint32_t #define PROGMEM #define pgm_read_byte(x) (*((char *)x)) #define pgm_read_word(x) (((*((unsigned char *)x + 1)) << 8) + (*((unsigned char *)x))) #define pgm_read_byte_near(x) (*((char *)x)) #define pgm_read_byte_far(x) (*((char *)x)) #define pgm_read_word_near(x) (((*((unsigned char *)x + 1)) << 8) + (*((unsigned char *)x))) #define pgm_read_word_far(x) ( ((*((unsigned char *)x + 1)) << 8) + (*((unsigned char *)x)))) #define PSTR(x) x #if defined F #undef F #endif #define F(X) (X) #endif #if defined(ESP8266) #define cbi(reg, bitmask) digitalWrite(bitmask, LOW) #define sbi(reg, bitmask) digitalWrite(bitmask, HIGH) #define pulse_high(reg, bitmask) \ sbi(reg, bitmask); \ cbi(reg, bitmask); #define pulse_low(reg, bitmask) \ cbi(reg, bitmask); \ sbi(reg, bitmask); #define cport(port, data) port &= data #define sport(port, data) port |= data #define swap(type, i, j) \ { \ type t = i; \ i = j; \ j = t; \ } #define fontbyte(x) cfont.font[x] #define regtype volatile uint32_t #define regsize uint32_t #endif #if defined(__SAMD51__) || defined(__SAMD21G18A__) #define Serial SERIAL_PORT_USBVIRTUAL #define cbi(reg, bitmask) *reg &= ~bitmask #define sbi(reg, bitmask) *reg |= bitmask #define pulse_high(reg, bitmask) \ sbi(reg, bitmask); \ cbi(reg, bitmask); #define pulse_low(reg, bitmask) \ cbi(reg, bitmask); \ sbi(reg, bitmask); #define cport(port, data) port &= data #define sport(port, data) port |= data #define swap(type, i, j) \ { \ type t = i; \ i = j; \ j = t; \ } #define fontbyte(x) cfont.font[x] #define regtype volatile uint32_t #define regsize uint32_t #endif #if defined(ESP32) #define cbi(reg, bitmask) digitalWrite(bitmask, LOW) #define sbi(reg, bitmask) digitalWrite(bitmask, HIGH) #define pulse_high(reg, bitmask) \ sbi(reg, bitmask); \ cbi(reg, bitmask); #define pulse_low(reg, bitmask) \ cbi(reg, bitmask); \ sbi(reg, bitmask); #define cport(port, data) port &= data #define sport(port, data) port |= data #define swap(type, i, j) \ { \ type t = i; \ i = j; \ j = t; \ } #define fontbyte(x) cfont.font[x] #define regtype volatile uint32_t #define regsize uint32_t #endif #if defined(__CPU_ARC__) #define cbi(reg, bitmask) *reg &= ~bitmask #define sbi(reg, bitmask) *reg |= bitmask #define pulse_high(reg, bitmask) \ sbi(reg, bitmask); \ cbi(reg, bitmask); #define pulse_low(reg, bitmask) \ cbi(reg, bitmask); \ sbi(reg, bitmask); #define cport(port, data) port &= data #define sport(port, data) port |= data #define swap(type, i, j) \ { \ type t = i; \ i = j; \ j = t; \ } #define fontbyte(x) pgm_read_byte(&cfont.font[x]) #define regtype volatile uint32_t #define regsize uint32_t #endif #if defined(RASPBERRY_PI) #define regtype volatile uint32_t #define regsize uint32_t #define byte uint8_t #define cbi(reg, bitmask) digitalWrite(bitmask, LOW) #define sbi(reg, bitmask) digitalWrite(bitmask, HIGH) #define PROGMEM #define PSTR(x) x #if defined F #undef F #endif #define F(X) (X) #endif #if defined(ARDUINO_ARCH_NRF52) #define cbi(reg, bitmask) digitalWrite(bitmask, LOW) #define sbi(reg, bitmask) digitalWrite(bitmask, HIGH) #define pulse_high(reg, bitmask) \ sbi(reg, bitmask); \ cbi(reg, bitmask); #define pulse_low(reg, bitmask) \ cbi(reg, bitmask); \ sbi(reg, bitmask); #define cport(port, data) port &= data #define sport(port, data) port |= data #define swap(type, i, j) \ { \ type t = i; \ i = j; \ j = t; \ } #define fontbyte(x) cfont.font[x] #define regtype volatile uint32_t #define regsize uint32_t #endif #if defined(TEENSYDUINO) #define cbi(reg, bitmask) digitalWriteFast(bitmask, LOW) #define sbi(reg, bitmask) digitalWriteFast(bitmask, HIGH) #define pulse_high(reg, bitmask) \ sbi(reg, bitmask); \ cbi(reg, bitmask); #define pulse_low(reg, bitmask) \ cbi(reg, bitmask); \ sbi(reg, bitmask); #define cport(port, data) port &= data #define sport(port, data) port |= data #define swap(type, i, j) \ { \ type t = i; \ i = j; \ j = t; \ } #define fontbyte(x) cfont.font[x] #define regtype volatile uint8_t #define regsize uint8_t #endif #if defined(NRF52840_XXAA) #define cbi(reg, bitmask) digitalWrite(bitmask, LOW) #define sbi(reg, bitmask) digitalWrite(bitmask, HIGH) #define pulse_high(reg, bitmask) \ sbi(reg, bitmask); \ cbi(reg, bitmask); #define pulse_low(reg, bitmask) \ cbi(reg, bitmask); \ sbi(reg, bitmask); #define cport(port, data) port &= data #define sport(port, data) port |= data #define swap(type, i, j) \ { \ type t = i; \ i = j; \ j = t; \ } #define fontbyte(x) cfont.font[x] #define regtype volatile uint32_t #define regsize uint32_t #define PROGMEM #if defined F #undef F #endif #define F(X) (X) #endif #if defined(ARDUINO_ARCH_STM32) #define cbi(reg, bitmask) *reg &= ~bitmask #define sbi(reg, bitmask) *reg |= bitmask #define pulse_high(reg, bitmask) \ sbi(reg, bitmask); \ cbi(reg, bitmask); #define pulse_low(reg, bitmask) \ cbi(reg, bitmask); \ sbi(reg, bitmask); #define cport(port, data) port &= data #define sport(port, data) port |= data #define swap(type, i, j) \ { \ type t = i; \ i = j; \ j = t; \ } #define fontbyte(x) cfont.font[x] #define regtype volatile uint32_t #define regsize uint32_t #endif /****************************************************/ /* Sensor related definition */ /****************************************************/ #define BMP 0 #define JPEG 1 #define RAW 2 #define OV7670 0 #define MT9D111_A 1 #define OV7675 2 #define OV5642 3 #define OV3640 4 #define OV2640 5 #define OV9655 6 #define MT9M112 7 #define OV7725 8 #define OV7660 9 #define MT9M001 10 #define OV5640 11 #define MT9D111_B 12 #define OV9650 13 #define MT9V111 14 #define MT9T112 15 #define MT9D112 16 #define MT9V034 17 #define MT9M034 18 #define OV2640_160x120 0 // 160x120 #define OV2640_176x144 1 // 176x144 #define OV2640_320x240 2 // 320x240 #define OV2640_352x288 3 // 352x288 #define OV2640_640x480 4 // 640x480 #define OV2640_800x600 5 // 800x600 #define OV2640_1024x768 6 // 1024x768 #define OV2640_1280x1024 7 // 1280x1024 #define OV2640_1600x1200 8 // 1600x1200 #define OV3640_176x144 0 // 176x144 #define OV3640_320x240 1 // 320x240 #define OV3640_352x288 2 // 352x288 #define OV3640_640x480 3 // 640x480 #define OV3640_800x600 4 // 800x600 #define OV3640_1024x768 5 // 1024x768 #define OV3640_1280x960 6 // 1280x960 #define OV3640_1600x1200 7 // 1600x1200 #define OV3640_2048x1536 8 // 2048x1536 #define OV5642_320x240 0 // 320x240 #define OV5642_640x480 1 // 640x480 #define OV5642_1024x768 2 // 1024x768 #define OV5642_1280x960 3 // 1280x960 #define OV5642_1600x1200 4 // 1600x1200 #define OV5642_2048x1536 5 // 2048x1536 #define OV5642_2592x1944 6 // 2592x1944 #define OV5642_1920x1080 7 #define OV5640_320x240 0 // 320x240 #define OV5640_352x288 1 // 352x288 #define OV5640_640x480 2 // 640x480 #define OV5640_800x480 3 // 800x480 #define OV5640_1024x768 4 // 1024x768 #define OV5640_1280x960 5 // 1280x960 #define OV5640_1600x1200 6 // 1600x1200 #define OV5640_2048x1536 7 // 2048x1536 #define OV5640_2592x1944 8 // 2592x1944 // Light Mode #define Auto 0 #define Sunny 1 #define Cloudy 2 #define Office 3 #define Home 4 #define Advanced_AWB 0 #define Simple_AWB 1 #define Manual_day 2 #define Manual_A 3 #define Manual_cwf 4 #define Manual_cloudy 5 // Color Saturation #define Saturation4 0 #define Saturation3 1 #define Saturation2 2 #define Saturation1 3 #define Saturation0 4 #define Saturation_1 5 #define Saturation_2 6 #define Saturation_3 7 #define Saturation_4 8 // Brightness #define Brightness4 0 #define Brightness3 1 #define Brightness2 2 #define Brightness1 3 #define Brightness0 4 #define Brightness_1 5 #define Brightness_2 6 #define Brightness_3 7 #define Brightness_4 8 // Contrast #define Contrast4 0 #define Contrast3 1 #define Contrast2 2 #define Contrast1 3 #define Contrast0 4 #define Contrast_1 5 #define Contrast_2 6 #define Contrast_3 7 #define Contrast_4 8 #define degree_180 0 #define degree_150 1 #define degree_120 2 #define degree_90 3 #define degree_60 4 #define degree_30 5 #define degree_0 6 #define degree30 7 #define degree60 8 #define degree90 9 #define degree120 10 #define degree150 11 // Special effects #define Antique 0 #define Bluish 1 #define Greenish 2 #define Reddish 3 #define BW 4 #define Negative 5 #define BWnegative 6 #define Normal 7 #define Sepia 8 #define Overexposure 9 #define Solarize 10 #define Blueish 11 #define Yellowish 12 #define Exposure_17_EV 0 #define Exposure_13_EV 1 #define Exposure_10_EV 2 #define Exposure_07_EV 3 #define Exposure_03_EV 4 #define Exposure_default 5 #define Exposure03_EV 6 #define Exposure07_EV 7 #define Exposure10_EV 8 #define Exposure13_EV 9 #define Exposure17_EV 10 #define Auto_Sharpness_default 0 #define Auto_Sharpness1 1 #define Auto_Sharpness2 2 #define Manual_Sharpnessoff 3 #define Manual_Sharpness1 4 #define Manual_Sharpness2 5 #define Manual_Sharpness3 6 #define Manual_Sharpness4 7 #define Manual_Sharpness5 8 #define Sharpness1 0 #define Sharpness2 1 #define Sharpness3 2 #define Sharpness4 3 #define Sharpness5 4 #define Sharpness6 5 #define Sharpness7 6 #define Sharpness8 7 #define Sharpness_auto 8 #define EV3 0 #define EV2 1 #define EV1 2 #define EV0 3 #define EV_1 4 #define EV_2 5 #define EV_3 6 #define MIRROR 0 #define FLIP 1 #define MIRROR_FLIP 2 #define high_quality 0 #define default_quality 1 #define low_quality 2 #define Color_bar 0 #define Color_square 1 #define BW_square 2 #define DLI 3 #define Night_Mode_On 0 #define Night_Mode_Off 1 #define Off 0 #define Manual_50HZ 1 #define Manual_60HZ 2 #define Auto_Detection 3 /****************************************************/ /* I2C Control Definition */ /****************************************************/ #define I2C_ADDR_8BIT 0 #define I2C_ADDR_16BIT 1 #define I2C_REG_8BIT 0 #define I2C_REG_16BIT 1 #define I2C_DAT_8BIT 0 #define I2C_DAT_16BIT 1 /* Register initialization tables for SENSORs */ /* Terminating list entry for reg */ #define SENSOR_REG_TERM_8BIT 0xFF #define SENSOR_REG_TERM_16BIT 0xFFFF /* Terminating list entry for val */ #define SENSOR_VAL_TERM_8BIT 0xFF #define SENSOR_VAL_TERM_16BIT 0xFFFF // Define maximum frame buffer size #if (defined OV2640_MINI_2MP) #define MAX_FIFO_SIZE 0x5FFFF // 384KByte #elif (defined OV5642_MINI_5MP || defined OV5642_MINI_5MP_BIT_ROTATION_FIXED || defined ARDUCAM_SHIELD_REVC) #define MAX_FIFO_SIZE 0x7FFFF // 512KByte #else #define MAX_FIFO_SIZE 0x7FFFFF // 8MByte #endif /****************************************************/ /* ArduChip registers definition */ /****************************************************/ #define RWBIT 0x80 // READ AND WRITE BIT IS BIT[7] #define ARDUCHIP_TEST1 0x00 // TEST register #if !(defined OV2640_MINI_2MP) #define ARDUCHIP_FRAMES 0x01 // FRAME control register, Bit[2:0] = Number of frames to be captured //On 5MP_Plus platforms bit[2:0] = 7 means continuous capture until frame buffer is full #endif #define ARDUCHIP_MODE 0x02 // Mode register #define MCU2LCD_MODE 0x00 #define CAM2LCD_MODE 0x01 #define LCD2MCU_MODE 0x02 #define ARDUCHIP_TIM 0x03 // Timming control #if !(defined OV2640_MINI_2MP) #define HREF_LEVEL_MASK 0x01 // 0 = High active , 1 = Low active #define VSYNC_LEVEL_MASK 0x02 // 0 = High active , 1 = Low active #define LCD_BKEN_MASK 0x04 // 0 = Enable, 1 = Disable #if (defined ARDUCAM_SHIELD_V2) #define PCLK_REVERSE_MASK 0x08 // 0 = Normal PCLK, 1 = REVERSED PCLK #else #define PCLK_DELAY_MASK 0x08 // 0 = data no delay, 1 = data delayed one PCLK #endif // #define MODE_MASK 0x10 //0 = LCD mode, 1 = FIFO mode #endif // #define FIFO_PWRDN_MASK 0x20 //0 = Normal operation, 1 = FIFO power down // #define LOW_POWER_MODE 0x40 //0 = Normal mode, 1 = Low power mode #define ARDUCHIP_FIFO 0x04 // FIFO and I2C control #define FIFO_CLEAR_MASK 0x01 #define FIFO_START_MASK 0x02 #define FIFO_RDPTR_RST_MASK 0x10 #define FIFO_WRPTR_RST_MASK 0x20 #define ARDUCHIP_GPIO 0x06 // GPIO Write Register #if !(defined(ARDUCAM_SHIELD_V2) || defined(ARDUCAM_SHIELD_REVC)) #define GPIO_RESET_MASK 0x01 // 0 = Sensor reset, 1 = Sensor normal operation #define GPIO_PWDN_MASK 0x02 // 0 = Sensor normal operation, 1 = Sensor standby #define GPIO_PWREN_MASK 0x04 // 0 = Sensor LDO disable, 1 = sensor LDO enable #endif #define BURST_FIFO_READ 0x3C // Burst FIFO read operation #define SINGLE_FIFO_READ 0x3D // Single FIFO read operation #define ARDUCHIP_REV 0x40 // ArduCHIP revision #define VER_LOW_MASK 0x3F #define VER_HIGH_MASK 0xC0 #define ARDUCHIP_TRIG 0x41 // Trigger source #define VSYNC_MASK 0x01 #define SHUTTER_MASK 0x02 #define CAP_DONE_MASK 0x08 #define FIFO_SIZE1 0x42 // Camera write FIFO size[7:0] for burst to read #define FIFO_SIZE2 0x43 // Camera write FIFO size[15:8] #define FIFO_SIZE3 0x44 // Camera write FIFO size[18:16] /****************************************************/ /****************************************************************/ /* define a structure for sensor register initialization values */ /****************************************************************/ struct sensor_reg { uint16_t reg; uint16_t val; }; /****************************************************************/ /* define a structure for sensor register initialization values */ /****************************************************************/ class ArduCAM { public: ArduCAM(void); ArduCAM(byte model, int CS); void InitCAM(void); void CS_HIGH(void); void CS_LOW(void); void flush_fifo(void); void start_capture(void); void clear_fifo_flag(void); uint8_t read_fifo(void); uint8_t read_reg(uint8_t addr); void write_reg(uint8_t addr, uint8_t data); uint32_t read_fifo_length(void); void set_fifo_burst(void); void set_bit(uint8_t addr, uint8_t bit); void clear_bit(uint8_t addr, uint8_t bit); uint8_t get_bit(uint8_t addr, uint8_t bit); void set_mode(uint8_t mode); uint8_t bus_write(int address, int value); uint8_t bus_read(int address); // Write 8 bit values to 8 bit register address int wrSensorRegs8_8(const struct sensor_reg *); // Write 16 bit values to 8 bit register address int wrSensorRegs8_16(const struct sensor_reg *); // Write 8 bit values to 16 bit register address int wrSensorRegs16_8(const struct sensor_reg *); // Write 16 bit values to 16 bit register address int wrSensorRegs16_16(const struct sensor_reg *); // Read/write 8 bit value to/from 8 bit register address byte wrSensorReg8_8(int regID, int regDat); byte rdSensorReg8_8(uint8_t regID, uint8_t *regDat); // Read/write 16 bit value to/from 8 bit register address byte wrSensorReg8_16(int regID, int regDat); byte rdSensorReg8_16(uint8_t regID, uint16_t *regDat); // Read/write 8 bit value to/from 16 bit register address byte wrSensorReg16_8(int regID, int regDat); byte rdSensorReg16_8(uint16_t regID, uint8_t *regDat); // Read/write 16 bit value to/from 16 bit register address byte wrSensorReg16_16(int regID, int regDat); byte rdSensorReg16_16(uint16_t regID, uint16_t *regDat); void OV2640_set_JPEG_size(uint8_t size); void OV3640_set_JPEG_size(uint8_t size); void OV5642_set_JPEG_size(uint8_t size); void OV5640_set_JPEG_size(uint8_t size); void OV5642_set_RAW_size(uint8_t size); void OV2640_set_Light_Mode(uint8_t Light_Mode); void OV3640_set_Light_Mode(uint8_t Light_Mode); void OV5642_set_Light_Mode(uint8_t Light_Mode); void OV5640_set_Light_Mode(uint8_t Light_Mode); void OV2640_set_Color_Saturation(uint8_t Color_Saturation); void OV3640_set_Color_Saturation(uint8_t Color_Saturation); void OV5642_set_Color_Saturation(uint8_t Color_Saturation); void OV5640_set_Color_Saturation(uint8_t Color_Saturation); void OV2640_set_Brightness(uint8_t Brightness); void OV3640_set_Brightness(uint8_t Brightness); void OV5642_set_Brightness(uint8_t Brightness); void OV5640_set_Brightness(uint8_t Brightness); void OV2640_set_Contrast(uint8_t Contrast); void OV3640_set_Contrast(uint8_t Contrast); void OV5642_set_Contrast(uint8_t Contrast); void OV5640_set_Contrast(uint8_t Contrast); void OV2640_set_Special_effects(uint8_t Special_effect); void OV3640_set_Special_effects(uint8_t Special_effect); void OV5642_set_Special_effects(uint8_t Special_effect); void OV5640_set_Special_effects(uint8_t Special_effect); void OV3640_set_Exposure_level(uint8_t level); void OV3640_set_Sharpness(uint8_t Sharpness); void OV3640_set_Mirror_Flip(uint8_t Mirror_Flip); void OV5642_set_hue(uint8_t degree); void OV5642_set_Exposure_level(uint8_t level); void OV5642_set_Sharpness(uint8_t Sharpness); void OV5642_set_Mirror_Flip(uint8_t Mirror_Flip); void OV5642_set_Compress_quality(uint8_t quality); void OV5642_Test_Pattern(uint8_t Pattern); void OV5640_set_EV(uint8_t EV); void OV5640_set_Night_Mode(uint8_t Night_mode); void OV5640_set_Banding_Filter(uint8_t Banding_Filter); void set_format(byte fmt); #if defined(RASPBERRY_PI) uint8_t transfer(uint8_t data); void transfers(uint8_t *buf, uint32_t size); #endif void transferBytes_(uint8_t *out, uint8_t *in, uint8_t size); void transferBytes(uint8_t *out, uint8_t *in, uint32_t size); inline void setDataBits(uint16_t bits); protected: regtype *P_CS; regsize B_CS; byte m_fmt; byte sensor_model; byte sensor_addr; }; #if defined OV7660_CAM #include "ov7660_regs.h" #endif #if defined OV7725_CAM #include "ov7725_regs.h" #endif #if defined OV7670_CAM #include "ov7670_regs.h" #endif #if defined OV7675_CAM #include "ov7675_regs.h" #endif #if (defined(OV5642_CAM) || defined(OV5642_MINI_5MP) || defined(OV5642_MINI_5MP_BIT_ROTATION_FIXED) || defined(OV5642_MINI_5MP_PLUS)) #include "ov5642_regs.h" #endif #if (defined(OV3640_CAM) || defined(OV3640_MINI_3MP)) #include "ov3640_regs.h" #endif #if (defined(OV2640_CAM) || defined(OV2640_MINI_2MP) || defined(OV2640_MINI_2MP_PLUS)) #include "ov2640_regs.h" #endif #if defined MT9D111A_CAM || defined MT9D111B_CAM #include "mt9d111_regs.h" #endif #if defined MT9M112_CAM #include "mt9m112_regs.h" #endif #if defined MT9V111_CAM #include "mt9v111_regs.h" #endif #if (defined(OV5640_CAM) || defined(OV5640_MINI_5MP_PLUS)) #include "ov5640_regs.h" #endif #if defined MT9M001_CAM #include "mt9m001_regs.h" #endif #if defined MT9T112_CAM #include "mt9t112_regs.h" #endif #if defined MT9D112_CAM #include "mt9d112_regs.h" #endif #if defined MT9M034_CAM #include "mt9m034_regs.h" #endif #endif
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