DIY - PIC：PIC18F4550 PWM 控制 LED 開關程式 (五十五)

DIY - PIC：PIC18F4550 PWM 控制 LED 開關程式 (五十五)：

程式的是從 LED 光暗程式 (DIY - 電子：PIC18F4550 PWM 控制 LED 光暗程式 (五十四) ) 修改成為 LED 開關程式，當按鍵按下，LED 便會慢慢地發亮，LED 便會亮著，如果再按一下按鍵，LED 便會慢慢地暗，直至熄滅。

▲ PIC18F4550 PWM控制LED開關程式流程圖

主程式：

void main(void) {     //                              1234567890123456                    char LCD_name[] ="BWS PWM - RC1 v2";     char LCD_name2[]="                                  ";     unsigned char dc;                       // Duty Cycle unsigned char key;                     // Keyboard Status unsigned char keyon = 0;           // Key On = 1            ADCON0 = 0x00;                     // Disable the AD converter     ADCON1 = 0x0F;                     // Set all ports to digital     TRISB = 0b11100000;              // Set PORTB RB5 as Key In     TRISC = 0b11111001;              // Set PORTC C1 and C2 as PWM output     LATC  = 0b00000000 ;             // Clear PORTC            // Initialise LCD     OpenXLCD(FOUR_BIT&LINES_5X7);   // Init the LCD Display     while(BusyXLCD());     WriteCmdXLCD(BLINK_OFF & CURSOR_OFF );      while(BusyXLCD());         stdout = _H_USER;                    // Redirect I/O to LCD     LcdSetLine1();                            // Put cursor on start of line 1     putsXLCD(LCD_name);             // Display text //Configure CCP module as (PR2+1)*4*TOSC*T2_PS     PR2            = 0b10011011;        // PWM Frequency = 152 = 2KHz = 0.5ms     T2CON      = 0b00000111;        // 1:16     CCP1CON = 0b00001100;        // PWM Mode P1A/P1C/P1B/P1D=H <5:4> DC     CCP2CON = 0b00111100;        // PWM Mode P2A/P2C/P2B/P2D=H                                                         // Duty Cycle CCP1CON<5:4>+CCPR1L         while(1)     {         // PWM resolution is 10 bits don't use last 2 less significant bits CCPxCON,         // so only CCPRxL have to be touched to change duty cycle         key = 1;           key = PORTBbits.RB5;         if (key == 0) {             if (keyon == 0) {                     keyon = 1;                    for(dc = 0 ; dc < 128 ; dc++){                     CCPR1L = dc ;                     CCPR2L = 128 - dc ;                     LcdSetLine2();        // Put cursor on start of line 2                     printf("LED ON  DC=%04i", CCPR2L);                     }             } else {                     keyon = 0;                    for(dc = 128 ; dc > 0 ; dc--){                     CCPR1L = dc ;                     CCPR2L = 128 - dc ;                     LcdSetLine2();        // Put cursor on start of line 2                     printf("LED OFF DC=%04i", CCPR2L);                     }             } // End if keyon         } // End if key     } // End While }

▲當按一下鍵，LED 會自動慢慢變亮

▲再按一下鍵，LED 會自動慢慢變暗

▲ LCD 顯示LED狀態及PWM 的Duty Cycle

2011 年 04 月 10 日 天氣報告
氣溫：22.3 度 @ 23:00 
相對濕度：百分之80%  
天氣：天色大致良好