Pico HSM uses the led to indicate the current status. Four states are available:
Press to confirm
The Led is almost on all the time. It goes off for 100 milliseconds every second. In this state, you have to press BOOTSEL button to confirm operation (i.e., confirm a signature generation). The operation will timeout in 15 seconds, denying the request.
In idle mode, the Pico HSM goes to sleep. It waits for a command and it is awaken by the driver. The Led is almost off all the time. It goes on for 500 milliseconds every second.
In active mode, the Pico HSM is awaken and ready to receive a command. It blinks four times in a second.
While processing, the Pico HSM is busy and cannot receive additional commands until the current is processed. In this state, the Led blinks 20 times in a second.