Project 8 – Using fixed-point arithmetic in our temperature sensor

Previously our temperature sensor output wasn’t available for 16 seconds, the time it takes to fill the smoothing FIFO. This project will show us how we can get accurate outputs during those first 16 seconds.

Let’s look at how we can optimize our temperature averaging to handle the 16 seconds where the temperature is incorrectly calculated. This happens because we are dividing an invalid temperature over the first 15 clock cycles.

There are cases where either a delay or inaccurate results can’t occur. I was asked a job interview question regarding how to make sure that the output from this type of filter was valid during the bring-up time. This is a practical question that you may need to address someday.

Using fixed-point arithmetic to clean up the bring-up time

First, let’s look at what a fixed-point scaling factor looks like. In the end, we want to scale to that...