The problem of calling ds18b20 through a single bus

1. The single bus has high timing requirements, and the delay should be long enough, at least 93.57ms (9 bits), and at most 750ms (12 bits), and then the correct data can be read.

2. The read temperature bytes should be usedUnsigned char or int storage, the temperature read directly with char will be problematic, because char has only seven bits, and one is the sign bit.