DIY - PIC：PIC18F4550 數字溫度計 – DS18B20 電路程式 (一百三十四)

DIY - PIC：PIC18F4550 數字溫度計 – DS18B20 電路程式  (一百三十四)：

Microchip PIC18F4550 + DS18B20 數字溫度計電路程式，程式是利用 DS18B20 內置溫度處理電路，18F4550 送出一個 T [44H] 轉換命令，DS18B20 啟動溫度測量和 A-to-D 轉換，轉換後，溫度數據會存儲在 2-byte 的暫存器 (scratchpad memory) 內的溫度寄存器 (temperature register) 和 DS18S20 返回到空閒狀態，Master 會發出“讀取時段”(Read Time Slots) ，並將溫度資料接收，程式會讀取接收資料數據，然後在 LC1602 顯示屏顯示溫度。

PIC18F4550 + DS18B20 數字溫度計程式流程圖

▼主程式

void main(void) {     char LCD_name[] ="BWS DS18B20 2012";     char LCD_name2[]="                ";  int i;  unsigned int timeout=0;  char data;         // Variables for Temperature         unsigned short TempHL, TempH, TempL;  char Buf[] ="                ";  unsigned int Temp_whole, Temp_fraction, Temp_value;         signed int  Temp_pinF, Temp_pinC;         unsigned short C_Neg=0, F_Neg=0;         char Temp_sign;         //ADCON0 = 0x00;                      // Disable the AD converter         //ADCON1 = 0x0F;                      // Set all ports to digital         TRISA = 0b00000001;                // Setup RA0=Input RA1=Output         TRISB = 0b00100000;                // Setup RB0=Input         // 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         while(1)         {             LATAbits.LATA1 = 1;     // RA0=1 LED=ON Scope=1                   if (reset_ow()==0){                            write_byte_ow(0xCC);                            write_byte_ow(0x44);             Delay10KTCYx(180);             // Delay:750ms 10,000x2x(4x0.05us)= 4ms                        reset_ow();                        write_byte_ow(0xCC);                        write_byte_ow(0xBE);                 TempL = read_byte_ow();               // Read LSB                 TempH = read_byte_ow();               // Read MSB                 Temp_value = (TempH << 8) + TempL;                 Temp_sign  = '+';                 C_Neg      = Temp_value & 0x8000;                         // Test MSB                 if (C_Neg) {                                                              // If Negative                         Temp_value = (Temp_value ^ 0xFFFF) +1;      // 2's comp                     Temp_sign = '-';                                                    // Sign = Negative                 }                 Temp_pinC = (6 * Temp_value) + Temp_value/4;    // Multiple by 6.25                 Temp_whole    = Temp_pinC / 100;                         // Separate Digi & Fraction                 Temp_fraction = Temp_pinC % 100;                       // Fraction                 sprintf(Buf,"%04u.%02uC",Temp_whole,Temp_fraction);    // Put Temp into Buf                 Buf[0] = Temp_sign;                         // Buf0 = Sign                 LcdSetLine2();                                 // Put cursor on start of line 2                 putsXLCD(Buf);                                // Display Content                 } else {                 LcdSetLine2();                                 // Put cursor on start of line 2                 putsXLCD(LCD_name2);                 // Display Content                 }            LATAbits.LATA1 = 0;                     // RA0=0 LED=OFF Scope=50ms            Delay10KTCYx(240);                   // 10,000 x 1 x (4 x 0.05us) = 2ms                                                                // Scope = 2ms         } // End While }

18F4550 + DS18B20數字溫度計

LCD 1602 顯示溫度 +30.12℃

2012 年 6 月15日 天氣報告

氣溫：28.2 度 @ 22:20

相對濕度：百分之84%

天氣：大致多雲