1. Article purpose[edit source]
The purpose of this article is to explain how to monitor HSE clock. If HSE is used in your clock tree, this can be a good idea to monitoring HSE to detect and avoid over frequency. The LPTimer mechanism will detect an over frequency and trig a tamper event which ....
2. How to activate the monitoring[edit source]
By default, the HSE monitor is disabled in soc device tree:
hse_monitor: hse-monitor { compatible = "st,freq-monitor"; counter = <&lptimer3 1 1 0 0>; status = "disabled"; };
To activate HSE monitor add this node in your board:
&hse_monitor { status = "okay"; };