ds18b20读取温度的完整程序

//mega8 7.3728MHz gcc编译通过，_delay_us(us) _delay_ms(ms)调用库函数
//初始化把dq设置为输出
#define ds18b20_dq PC5
#define set_ds18b20_dq_ddr() DDRC|=1<<ds18b20_dq
#define set_ds18b20_dq() PORTC|=1<<ds18b20_dq
#define clr_ds18b20_dq() PORTC&=~(1<<ds18b20_dq)
#define clr_ds18b20_dq_ddr() DDRC&=~(1<<ds18b20_dq)
#define in_ds18b20_dq() PINC&(1<<ds18b20_dq)

#define ds18b20_read_rom 0x33
#define ds18b20_match_rom 0x55
#define ds18b20_skip_rom 0xcc
#define ds18b20_search_rom 0xf0
#define ds18b20_alarm_search_rom 0xec
#define ds18b20_write_ram 0x4e
#define ds18b20_read_ram 0xbe
#define ds18b20_copy_ram 0x48
#define ds18b20_convert_tem 0x44
#define ds18b20_eecall_eeprom 0xb8
#define ds18b20_read_power_supply 0xb4
void reset_ds18b20(void)
{
clr_ds18b20_dq();
_delay_us(198);//100us
_