DS18B20一线制温度传感器

DS18B20一线制温度传感器时序,开发原理:
特性:
一线制,64位唯一性标识码
64-BIT LASERED ROM CODE Figure 6
8-BIT CRC 48-BIT SERIAL NUMBER 8-BIT FAMILY CODE (28h)
MSB   MSB LSB              LSB LSB                MSB
9-12位可配置温度传感

传输序列:
Step 1. Initialization
Step 2. ROM Command (followed by any required data exchange)
Step 3. DS18B20 Function Command (followed by any required data exchange)

Step 1,初始化:
Master低电平保持480us->Master拉高电平->等待DS18B20拉低电平(pulling low)->Master等待240us

READ/WRITE TIME SLOTS:
写:
写0:Master拉低电平并且保持60us->Master拉高电平
写1:Master拉低电平并且在15us内释放总线->释放总线后,上拉电阻把电平拉高
无论写1还是写0,Master一定先拉低电平
DS18B20在Master初始化后15-60us取样
读:只有Master发送度命令后,DS18B20才能传输数据
读0/1:Master拉低电平15us后采样