raspberry pi throttling key

vcgencmd get_throttled

docs:
https://www.raspberrypi.com/documentation/computers/os.html#get_throttled
https://www.raspberrypi.com/documentation/computers/config_txt.html#monitoring-core-temperature

0: under-voltage
1: arm frequency capped
2: currently throttled 
3: soft temperature limit active
16: under-voltage has occurred
17: arm frequency capping has occurred
18: throttling has occurred
19: soft temperature limit has occurred

Ex 1:
Hex              5              0              0              0              0
Binary  0  1  0  1     0  0  0  0     0  0  0  0     0  0  0  0     0  0  0  0
Bit#   19 18 17 16    15 14 13 12    11 10 09 08    07 06 05 04    03 02 01 00                  
                 ^ -- Bit 16 is on - Been under voltage (at least once)
           ^ ----- Bit 18 is on - Been throttled (at least once)
(Note: since bits 0-3 are zero, the Pi is not currently UV or throttled).

Ex 2:
Hex              D              0              0              0              0
Binary  1  1  0  1     0  0  0  0     0  0  0  0     0  0  0  0     0  0  0  0
Bit#   19 18 17 16    15 14 13 12    11 10 09 08    07 06 05 04    03 02 01 00    
                 ^ -- Bit 16 is on - Been under voltage (at least once)
           ^ -----  Bit 18 is on - Been throttled (at least once)
        ^ -------- Bit 19 is on - Soft temperature limit has occurred (at least once)
(Note: since bits 0-3 are zero, the Pi is not currently UV or throttled).