Revision 2:1d858fcb3cb5, committed 2019-10-24

Comitter:

lant19

Date:

Thu Oct 24 06:30:59 2019 +0000

Parent:

1:7f3c3ac6b20b

Commit message:

with Chinese

Changed in this revision

diff -r 7f3c3ac6b20b -r 1d858fcb3cb5 PCA9685.cpp
--- a/PCA9685.cpp	Fri Jul 24 09:03:58 2015 +0000
+++ b/PCA9685.cpp	Thu Oct 24 06:30:59 2019 +0000
@@ -1,17 +1,17 @@
 #include "PCA9685.h"
 #include "mbed.h"
 PCA9685::PCA9685(PinName sda, PinName scl, int addr) : i2c(sda, scl), _i2caddr(addr) {}
-
-void PCA9685::begin(void)
+//定义引脚与地址
+void PCA9685::begin(void)//初始化
 {
     reset();
 }
 
-void PCA9685::frequencyI2C(int freq)
+void PCA9685::frequencyI2C(int freq)//初始化
 {
     i2c.frequency(freq);
 }
-void PCA9685::write8(uint8_t address, uint8_t data)
+void PCA9685::write8(uint8_t address, uint8_t data)//写函数
 {
     char cmd[2];
     cmd[0] = address;
@@ -19,7 +19,7 @@
     i2c.write(_i2caddr, cmd, 2);
 }
 
-char PCA9685::read8(char address)
+char PCA9685::read8(char address)//读函数
 {
     i2c.write(_i2caddr, &address, 1);
     char rtn;
@@ -27,21 +27,21 @@
     return rtn;
 }
 
-void PCA9685::reset(void)
+void PCA9685::reset(void)//复位
 {
     write8(PCA9685_MODE1, 0x0);
 }
-void PCA9685::setPrescale(uint8_t prescale) {
+void PCA9685::setPrescale(uint8_t prescale) {    
     uint8_t oldmode = read8(PCA9685_MODE1);
     uint8_t newmode = (oldmode&0x7F) | 0x10; // sleep
     write8(PCA9685_MODE1, newmode); // go to sleep
     wait_ms(5);
-    write8(PCA9685_PRESCALE, prescale); // set the prescaler
+    write8(PCA9685_PRESCALE, prescale); // 设置预缩放
     write8(PCA9685_MODE1, oldmode);
     wait_ms(5);
     write8(PCA9685_MODE1, oldmode | 0xa1);
 }
-void PCA9685::setPWMFreq(float freq)
+void PCA9685::setPWMFreq(float freq) //设置频率
 {
     float prescaleval = 25000000;
     prescaleval /= 4096;

diff -r 7f3c3ac6b20b -r 1d858fcb3cb5 PCA9685.h
--- a/PCA9685.h	Fri Jul 24 09:03:58 2015 +0000
+++ b/PCA9685.h	Thu Oct 24 06:30:59 2019 +0000
@@ -77,23 +77,23 @@
 class PCA9685
 {
 public:
-    PCA9685(PinName sda, PinName scl, int addr = 0x80);
+    PCA9685(PinName sda, PinName scl, int addr = 0x80);//定义pca9685 地址为1+A5+A4+A3+A2+A1+A0+rw rw写为0 读为1
     void frequencyI2C(int freq);
-    void begin(void); //Initialize the controller
-    void reset(void); //Reset the controller
-    void setPrescale(uint8_t prescale);//setPrescale(prescale)
-    /** Set prescale
+    void begin(void); //初始化
+    void reset(void); //复位
+    void setPrescale(uint8_t prescale);//设置预缩放
+    /** set prescale
      *
      *  @param prescale: set scale for the PWM frequency
      *
      */
-    void setPWMFreq(float freq);//Set the pwm frequency
+    void setPWMFreq(float freq);//设置PWM频率 单位hz
     /** Set frequency
       *
       * @param frequency in Hz
       *
       */
-    void setPWM(uint8_t num, uint16_t on, uint16_t off);//SetPWM(channel, on, off)
+    void setPWM(uint8_t num, uint16_t on, uint16_t off);//SetPWM(通道数:0到15, 信号上升沿位置:0到4095, 下降沿位置:0到4095)不同舵机所需的上升沿到下降沿的长度不同
     /** Set the start (on) and the end (off) of the part of the PWM pulse of the channel
      *  @param channel : from 0 to 15 the channel the should be update
      *  @param  on: from 0 to 4095 the tick when the signal should pass from low to high