I have an oscillator which I need to measure using an AVR MCU running on an 8MHz Xtal. The output from the oscillator is driving the clock input of a 4024 counter. The freq. range on Q6 (input signal divided down by 128) is between 900 Hz and 140 KHz. My goal is to measure the freq. with the best precision I can using this simple hardware.
My plan is to enable the output from the counter (disable master reset) and measure the time it takes between that and until I detect a falling edge on Q6 which would mean counter overflow.
After I disable the master reset pin on the counter I start a counter running at 8MHz, when the falling edge on Q6 is detected the timer is stopped and the counter value is read. From these numbers I can calculate the input freq.
I’m wondering if this would be accurate enough?