DS18B20 如何检测单总线上有没有接温度探头DS18B20啊？

阳光2260

如题，  我主要是想检测单总线上有没有接DS18B20，请问有没有什么好的方法啊？

阳光2260

请路过的朋友帮忙一下啊

sammy902583

下Read ROM检测:

Read ROM [33h]
This command allows the bus master to read the DS18B20’s 8-bit family code, unique 48-bit serial
number, and 8-bit CRC. This command can only be used if there is a single DS18B20 on the bus. If
more than one slave is present on the bus, a data collision will occur when all slaves try to transmit at the
same time (open drain will produce a wired AND result).

阳光2260

sammy902583 发表于 2018-10-16 11:06
下Read ROM检测:

Read ROM [33h]

使用Read ROM[33h]的话，如果没有接温度探头ds18b20，是不是读出的64位值都为0xFF啊？

csmjmcc

This command allows the bus master to read the DS18B20’s 8-bit family code, unique 48-bit serial
number, and 8-bit CRC. This command can only be used if there is a single DS18B20 on the bus. If
more than one slave is present on the bus, a data collision will occur when all slaves try to transmit at the
same time (open drain will produce a wired AND result).

英文较差，这段不是说：仅能单颗芯片在总线上，才能这样使用；多颗会发生冲突。??
感觉这方案不可行。

sammy902583

其实应该不用那么麻烦.
看看原子的代码, 里面已经有检测的程序了, 修改完善一下应该是可以达到版主的需求.
只是有多颗在总线的话, 应该也是要再改代码...

sppz

初始化后有响应
之后通过已知的ROM ID遍历确定设备是否正常
昨天读的手册,感觉大概是这样