CPU frequency thermal cap

Browse source code on GitHub

Overview

This sample demonstrates the CPU frequency thermal cap. The on-demand CPU frequency policy selects the requested P-state from CPU load, while the thermal cap limits the highest-performance P-state allowed by die temperature.

The board overlay enables the board die temperature sensor and configures low thermal trip points so the cap behavior is easy to observe during the sample. Product firmware should choose trip points for its own thermal design.

The sample does not automatically cycle the die temperature through the configured range. To observe all trip points, use a controlled external heat source to warm the board and let it cool back below the release thresholds.

Building and Running

Build and run this sample as follows:

west build -b frdm_mcxn236 samples/subsys/cpu_freq/thermal_cap
west flash

Sample Output

CPUFreq thermal cap sample
trip 0: 25.000 C -> cap pstate-1, release at 22.000 C
trip 1: 40.000 C -> cap pstate-2, release at 37.000 C

die temperature: 24.875 C, thermal cap: none
die temperature: 25.125 C, thermal cap: pstate-1
die temperature: 40.250 C, thermal cap: pstate-2