Newly Defined Button Evaluation Kit - Low Frequency Timer Test

小屋22

Newly Defined Button Evaluation Kit - Low Frequency Timer Test [Copy link]

 

The frequency of the low-frequency clock timer is 32kHz, and an external 32.768kHz crystal oscillator can be connected for more accurate timing and providing real-time time.

Low frequency timer, the maximum frequency is 15.6ms to generate an interrupt, and the minimum frequency is 32s to generate an interrupt

The following parameters should be based on 32.768Hz. The time output by the 32kHz timer will have deviations.

Here you can use an oscilloscope to roughly check whether the time is the same as the setting. The test method is to flip the IO port in the interrupt processing callback function of the timer. The flipping of the IO port has almost no effect on the millisecond-level delay. The position of P05 can be seen from the PCB board provided by the official.

Let me capture it with my low-profile oscilloscope. Any errors may be caused by the oscilloscope.

The signal with the highest test frequency here has a BTM period of 15.625ms, and the period read out by the oscilloscope is about 15.425ms, which is basically consistent.

The setting is 250ms, and the oscilloscope reading is 244ms, which is basically consistent.

秦天qintian0303

There is still a big error between 32kHz and 32.768kHz, and the timing error will accumulate over a long period of time.