DIY - PIC：PIC18F4550 Timer0 1秒鐘計時器程式 (一百六十九)

DIY - PIC：PIC18F4550 Timer0 1秒鐘計時器程式 (一百六十九) ：

這是一個利用 Timer0 和 Interrupt 篇寫出來的 1 秒鐘 (1 second) 計時器程式，程式會將設定 Timer0 中斷和寫入 59286 到 Timer0，Timer0 便會每 10ms 中斷一次，而中斷程式會用 Counter 計算 100次 (10ms × 100 = 1s) 便會熄滅 RA1 的 LED，到 Counter計算至 200次便會點亮 RA1 的 LED 並重置 Counter。

PIC18F4550 Timer0 1秒鐘計時器實驗

Timer0 1秒鐘計時器程式：

void main (void) {                  char LCD_name[]="BWS Timer=1S RA1";     unsigned int i;     unsigned int timeout=0;     char data;     ADCON0 = 0x00;              // Disable the AD converter     ADCON1 = 0x0F;              // Set all ports to digital     TRISA = 0b00000000;     // Setup PORTA as Output     // 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         OpenTimer0         (                TIMER_INT_ON &       // interrupt: ON                T0_16BIT &                   // 16 bit mode vs 8bit mode (T0_8BIT)                T0_SOURCE_INT &    // use internal clock                T0_PS_1_8                            // 1-bit 8/8 vs                                // 1:1/2/4/8/16/32/128/256         );         WriteTimer0 (59286);                // Preset Timer0 value 59286         RCONbits.IPEN = 0;                  // Interrupt Priority Control: OFF                                   // (RCON register IPEN bit = 0)         INTCONbits.TMR0IE = 1;        // Timer 0 interrupt enable         INTCONbits.PEIE = 1;              // peripheral interrupt enable         // INTCON register bit b6: low interrupt enable/disable         // (When interrupt priority control)         INTCONbits.GIE = 1;                // all interrupt enable         // INTCON register bit b7: high interrupt enable/disable         // (When interrupt priority control)         while (1)       // wait for interrupt doing nothing     {            i=SecondCount/100;            sprintf(glb_Buf,"Second=%1u",i); // Put Temp into Buf            LcdSetLine2();            putsXLCD(glb_Buf);         // Display Content     } } // End main

Timer0 中斷副程式：

void high_isr (void) {         INTCONbits.TMR0IF = 0;        // Timer 0 interrupt flag to 0         WriteTimer0 (59286);             // 0.05μsec × 4 × 8 × 6250 = 10000μsec = 10msec                                                        // (FOSC = HS at the system clock 20MHz)                                                       // 256 × 256 - 6250 = 59286                                                       // 16 bit timer overflow interrupt occurs         SecondCount ++;         TimeCount ++;                        // 10msec for each increment         if (TimeCount ＜100)             // count of 100 or less (1000msec = 10msec × 100)         {                 LATAbits.LATA1 = 0;    //RA0 = 0 LED: OFF Scope=0         }         else if (TimeCount ＜200)    // count from 100 to 200 (2000msec = 10msec × 100)         {                 LATAbits.LATA1 = 1;    // RA0 = 1 LED: ON Scope=1         }         else TimeCount = 0;             // Reset count = 0 }



RA1 的 LED 點亮

RA1 的 LED 熄滅

2013年5月15日 天氣報告

氣溫：28.4 度 @ 22:30

相對濕度：百分之84%

天氣：微雨