18B20 C procedure
// Access DQ and VCC 4.7K pull-up resistor #include "reg52.h" #include "intrins.h" #include "1602.c" #define uchar unsigned char # Define uint unsigned int // # Define Clearscreen LCD_EN_COMMAND (0x01) 1602 clear screen sbit dq = "p1" ^ 0; / * Operation command code Skip ROM 0XCC Send Temperature Conversion 0xBE Write EEPROM 0x4E * /
///////////// low level driver routine /////////// void Init18B20 (void); // initialize void Write18B20 (uchar ch); // write data unsigned char Read18B20 (void); // read data void Delay15 (uchar n); void Delay10ms (uint delay_num); void Display (void); ///////////////////// ///////////////////////////////////////////////////////////////////////////////////////////////////////S , 87, 93}; Code Uchar Decimall [] = {00, 25, 50, 75, 00, 25, 50, 75, 200, 25, 50, 75, 100, 25, 50, 75};
Uint ResultTemperatureH, ResultTemperatureLH, ResultTemperatureLLL; / / Elear, decimal high, decimal low uint resultignal; // symbol bit
Main () {uint temh, teml, delay, k = 0; for (;;) {init18b20 ();
Write18b20 (0xcc); // Skip ROM _NOP_(); // Write18B20 (0x4e); // Write EEPROM // Write18B20 (0x00); // / w w18b20 (0x00); // TL WRITE18B20 (0x7f); // 12 BITS temperature resolution init18b20 ();
Write18b20 (0xcc); // Skip ROM _NOP_();
Write18b20 (0x44); // Send Temperature Conversion Instruction Delay10ms (25); Delay10ms (25); Delay10ms (25); Delay10ms (25); // Waiting 1s Conversion
INIT18B20 (); Write18B20 (0xcc); // Skip ROM WRITE18B20 (0xBE); // Send Temperature Conversion Instruction Teml = "READ18B20" (); // Read Light Temperature Value Temh = "Read18B20" (); // Read High temperature value
Delay10ms (2); temh = (temh<<4) | (Teml>>4); teml = "teml" & 0x0f; // Take low 4-bit IF (Temh & 0x80) {temh = ~ temh; teml = ~ Teml + 1; ResultSignal = "1"; // negative} else resultignal = "0"; //
ResultTemperatureelh = "decimalh" [TEML]; ResultTemperatureEll = "decimall" [TEML]; resulttemperatureureh = "temh"; display ();
For (delay = 0; delay<60000; delay ++); for (delay = 0; delay<20000; delay ++);}}
Void Display (void) {uint i, j, q; lcd_init (); clearscreen; lcd_en_command (0x01); delay_nms (2); Q = "ResultTemperatureH / 100"; i = (ResultTemperatureH% 100) / 10; j = " ResultTemperatureH - "(i * 10 + q * 100); LCD_write_string (0, LINE1," Jaq1217 18B20 "); if (ResultSignal) {LCD_write_string (0, LINE2," T is: -. ");} else {LCD_write_string ( 0, LINE2, "T IS: +.");} LCD_WRITE_CHAR (0x07, Line2, Q | 0x30); LCD_WRITE_CHAR (0x08, Line2, I | 0x30); LCD_WRITE_CHAR (0x09, Line2, J | 0x30); LCD_WRITE_CHAR (0x0b , LINE2, (ResultTemperatureLH / 10) | 0x30); LCD_write_char (0x0c, LINE2, (ResultTemperatureLH% 10) | 0x30); LCD_write_char (0x0d, LINE2, (ResultTemperatureLL / 10) | 0x30); LCD_write_char (0x0e, LINE2, (ResultTemperatureLL % 10) | 0x30);
UNSIGNED Char {UNSIGNED CHAR CH; Unsigned Char q;
For (q = 0; q<8; q ++) {CH = CH>>1; DQ = "0"; _nop_(); dq = "1"; _nop _(); _nop _(); _nop_(); _nop_(); if (dq == 1) {CH = "CH | 0x80";
Else {CH = "CH" & 0x7f;} delay15 (3); DQ = "1";} Return (CH);}
Void write18b20 (uchar i; for (i = 0; I<8; i ++) {dq = "0"; delay15 (1); dq = "ch" & 0x01; delay15 (3); dq = "1 "; CH =" ch ">>1; _nop_();}}
void Init18B20 (void) {DQ = "0"; Delay15 (33); // delay is at least 480us DQ = "1"; Delay15 (10); // least delay 100us / * if (DQ == 1) return 0; // Initialization fail else return 1; DQ = 1; DELAY15 (18); * /}
void Delay15 (uchar n) {do {_nop_(); _nop_(); _nop_(); _nop_(); _nop_(); _nop_(); _nop_(); _nop_(); _nop_(); _nop_(); _nop_(); _nop_(); _nop_(); n-;} while (n);} void delay_num) {uchar i; while (delay_num--) {for (i = 0; I<125; i ++ ) {;}}}, Technology area
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