read_meas.c

来自「Source code for driving RFM01 fm radio r」· C语言 代码 · 共 21 行

#include "./ds18x20.h"

/* reads temperature (scratchpad) of sensor with rom-code id
   output: subzero==1 if temp.<0, cel: full celsius, mcel: frac 
   in millicelsius*0.1
   i.e.: subzero=1, cel=18, millicel=5000 = -18,5000癈 */
uint8_t DS18X20_read_meas(uint8_t id[], uint8_t *subzero, 
	uint8_t *cel, uint8_t *cel_frac_bits)
{
	uint8_t i;
	uint8_t sp[DS18X20_SP_SIZE];
	
	OW_reset(); //**
	OW_command(DS18X20_READ, id);
	for ( i=0 ; i< DS18X20_SP_SIZE; i++ ) sp[i]=OW_byte_rd();
	if ( crc8( &sp[0], DS18X20_SP_SIZE ) ) 
		return DS18X20_ERROR_CRC;
	DS18X20_meas_to_cel(id[0], sp, subzero, cel, cel_frac_bits);
	return DS18X20_OK;
}