The PIC12F1822 microcontroller is programmed to count the input frequency during accurate 1 second by dividing the 8 MHz crystal. The CPU runs at 32MHz from a PLL. The counter measures the frequency for 0.1sec first, if the frequency is greater than 2MHz TMR0 pre-scaler divides by 4 to increase the input frequency range to 16MHz with resolution of 4Hz, when the frequency is below 2MHz TMR0 is set for no pre-scaling and the measurement is with resolution of 1Hz. The frequency is displayed with leading zeros removed down to 3 digits. The font used is 5x7 pixels universal font.
OLED screen is driven by software I2C. The 470R resistors are for reducing 5V to 3.3V. The OLED module is a 0.91" 128 X 32 pixel driven by I2C interface and using SSD1306 driver IC. The OLED display uses low power LEDs and suitable for battery operated frequency counter. Power can be reduced farther by reducing contrast.
OLED screen is driven by software I2C. The 470R resistors are for reducing 5V to 3.3V. The OLED module is a 0.91" 128 X 32 pixel driven by I2C interface and using SSD1306 driver IC. The OLED display uses low power LEDs and suitable for battery operated frequency counter. Power can be reduced farther by reducing contrast.