MSP430与DS18B20的C程序
发布时间：2008-10-22 21:53
发布者：MSP430
| #include //#define DELTA 256 // target DCO = DELTA*(4096) = 1048576 #define DELTA 244 // target DCO = DELTA*(4096) = 1048576 unsigned char err_flag=0; //unsigned char result=0; //unsigned char result1=0; unsigned int result=0; unsigned int result1=0; void Set_DCO (void); void delay(unsigned int dd); void delay1(unsigned char dd1); void reset(void); void write_command(unsigned char command); //unsigned char read_data(void); unsigned int read_data(void); void main(void) { WDTCTL = WDTPW + WDTHOLD; // Stop WDT Set_DCO(); // Set DCO /*P1DIR |= 0x01; // Set P1.0 to output direction for (; { P1OUT ^= 0x01; // Toggle P1.0 using exclusive-OR delay(250000); }*/ P1OUT |= BIT4; P1DIR |= BIT4; while(1) { reset(); write_command(0xcc); write_command(0x44); delay1(6); reset(); write_command(0xcc); write_command(0xBE); result = read_data(); reset(); write_command(0xcc); write_command(0xBE); result1 = read_data(); _NOP(); result = 0; } } void reset(void) { P1OUT &= ~BIT4; delay(150); P1DIR &= ~BIT4; //************************ /*delay(3); delay(15); if(P1IN&BIT4) {err_flag = 1;} else err_flag =0;*/ //***************************** delay(9); if(P1IN&BIT4) {err_flag = 1;} else err_flag =0; delay(125); P1OUT |= BIT4; P1DIR |= BIT4; } void write_command(unsigned char command) { unsigned char i; for(i=0;i<8;i++) { P1OUT &= ~BIT4; if(command&0x01) { //delay(2); _NOP(); _NOP(); _NOP(); _NOP(); //P1OUT |= BIT4; P1DIR &= ~BIT4; } command=command>>1; //delay(15); delay(20); //P1OUT |= BIT4; P1DIR &= ~BIT4; delay(3); P1OUT |= BIT4; P1DIR |= BIT4; } } //unsigned char read_data(void) unsigned int read_data(void) { //unsigned char data=0,i; unsigned int data=0,i; //data = 0; for(i=0;i<8;i++) //for(i=0;i<16;i++) { P1OUT &= ~BIT4; _NOP(); _NOP(); _NOP(); P1DIR &= ~BIT4; _NOP(); if(P1IN&BIT4) //{data |= 0x80;} {data |= 0x0001;} data = data<<1; delay(23); P1OUT |= BIT4; P1DIR |= BIT4; } return data; } void delay(unsigned int dd) { unsigned int i; for(i=0;i } void delay1(unsigned char dd1) { unsigned char i; for(i=0;i { delay(50000); } } //------------------------------------------------------------------------------ void Set_DCO (void) // Set DCO to selected frequency //------------------------------------------------------------------------------ { //#define DELTA 900 // target DCO = DELTA*(4096) = 3686400 //#define DELTA 256 // target DCO = DELTA*(4096) = 1048576 //#define DELTA 64 // target DCO = DELTA*(4096) = 262144 unsigned int Compare, ldcapture = 0; BCSCTL1 |= DIVA_3; // ACLK= LFXT1CLK/8 CCTL2 = CM_1 + CCIS_1 + CAP; // CAP, ACLK TACTL = TASSEL_2 + MC_2 + TACLR; // SMCLK, cont-mode, clear while (1) { while (!(CCIFG & CCTL2)); // Wait until capture occured CCTL2 &= ~CCIFG; // Capture occured, clear flag Compare = CCR2; // Get current captured SMCLK Compare = Compare - Oldcapture; // SMCLK difference ldcapture = CCR2; // Save current captured SMCLK if (DELTA == Compare) break; // If equal, leave "while(1)" else if (DELTA < Compare) // DCO is too fast, slow it down { DCOCTL--; if (DCOCTL == 0xFF) BCSCTL1--; // Did DCO role under?, Sel lower RSEL } else { DCOCTL++; if (DCOCTL == 0x00) BCSCTL1++; // Did DCO role over? Sel higher RSEL } } CCTL2 = 0; // Stop CCR2 TACTL = 0; // Stop Timer_A BCSCTL1 &= ~DIVA_3; } |
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