The timer clock was configured with the High speed internal RC oscillator (HSI) The 64Mhz clock was pre-scaled down to 8Mhz

Configured P in 13 port C with external switch configured with external interrupt triggered by falling edge , the switch is internally pulled down implying that it’s value will be 0 at reset.

Pin 6 port A was configured with alternate function of Timer 3 channel 1 to generate a PWM wave with varying frequency , Timer details Pre-scaler = 8000-1 frequency =8Mhz/7999= 1 khz Counter period = 0

Now , for a frequency of say 1Khz , we can change the counter period to 1000-1 , by directly addressing the Time register TIM3->ARR=1000-1 , Counter period value can be changed depending on the frequency required The interrupt was then enabled in NVIC settings. Implemented power optimization by calling the Enter_LowPowerMode() function that calls the GPIO_deinit function , this turns off all the oscillators and timers. When the LED is turned off.