The arithmetic used in lesson6 exercise1 puzzled me.

RE: The arithmetic used in lesson6 exercise1 puzzled me.

Naeem Maroof — Mon, 17 Jun 2024 12:32:01 GMT

The reason is that the two bytes that you have referred to have 2's complement representation:

So, the two's complement of -1 is 0xFF, and if you store this byte instead of 0x81, you would get -1C.

Chaoyue Ying — Tue, 11 Jun 2024 00:14:42 GMT

Hi,

After the if-condition,it will calculate the cTemp.

According to the formula,the result of cTemp is -127.Based on the previous assumptions,the result of cTemp should equal to -1.It puzzled me.

Naeem Maroof — Fri, 07 Jun 2024 12:43:53 GMT

Hi,

The code could have been written in different ways to implement as per the datasheet.

However, the calculations performed here gives correct result.

As you have said that [0x00 , 0x81] should give -2032;

Yes, it is giving -2032

in the first line of code temp becomes 2064

and then the if-condition corrects the result and temp becomes -2032