LCD TFT is digital display at its best, it displays versatile clear picture. The picture is built by entering the address and the color of a pixel or rectangle, so it's simple to use too.
Counter using PIC16F1827 drives the TFT SPI.
Included C code and circuit diagram. The LCD TFT module is a 1.8" 128 X160 pixel and has the driver ST7735
The frequency is displayed by 7 digits with leading zeros removed down to 3 digits. The picture displayed is based on universal text. The period is calculated. When input frequency is less than 1000Hz the period is displayed in us.
The counting is over a period of 1 second, generated by the 8 MHz crystal oscillator increased to 32MHz by the internal PLL. The max counting is 7 digits (8MHz) with resolution of 1Hz. Period of 1 sec is generated by TMR1 and CCP1.

LCD TFT is digital display at its best, it displays versatile clear picture. The picture is built by entering the address and the color of a pixel or rectangle, so it's simple to use too.
Counter using PIC16F628A drives the TFT with software SPI (slower SPI).
Included C code and circuit diagram. The LCD TFT module is a 1.8" 128 X160 pixel and has the driver ST7735
The frequency is displayed by 7 digits with leading zeros removed down to 3 digits. The picture displayed is based on universal text. The period is calculated. When input frequency is less than 1000Hz the period is displayed in us.
The counting is over a period of 1 second, generated by the 16 MHz crystal oscillator. The max counting is 7 digits (4MHz). I tested the counter at up to 2MHz. Period of 1 sec is generated by TMR1 and CCP1.
Code is for MPLABX v3.10 and compilers XC8 (ver1.45).

You are free to use the circuit diagram and the software with no limitations.

LCD TFT is digital display at its best, it displays versatile clear picture. The picture is built by entering the address and the color of a pixel or rectangle, so it's simple to use too.
The TFT is driven by hardware SPI.
Included C code and circuit diagram. The LCD TFT module is a 1.8" 128 X160 pixel and has the driver ST7735
The frequency is displayed by 7 digits with leading zeros removed down to 1 digit. The period is calculated. When input frequency is less than 1000Hz the period is displayed in us.
The counting is over a period of 1 second, generated by the 16 MHz crystal oscillator. The max counting is 7 digits (4MHz). Period of 1 sec is generated by TMR1 and CCP1.
Code is for MPLAB, MPLABX and compilers HI TECH or XC8 (ver1.45).

LCD TFT is digital display at its best, it displays versatile clear picture. The picture is built by entering the address and the color of a pixel or rectangle, so it's simple to use too.
The TFT is driven by hardware SPI.
Included C code and circuit diagram. The LCD TFT module is a 1.8" 128 X160 pixel and has the driver ST7735
The frequency is displayed by 7 digits with leading zeros removed down to 1 digit. The picture displayed is based on 7 segment. The period is calculated. When input frequency is less than 1000Hz the period is displayed in us.
The counting is over a period of 1 second, generated by the 8 MHz crystal oscillator. The max counting is 7 digits (4MHz). Period of 1 sec is generated by TMR1 and CCP1.
Code is for MPLABX and compiler XC8 (ver1.45).

Counter using Arduino Uno or Nano. Included ino file, C file for font, keep the ino file and C file in the same folder. The OLED module is a 0.96" 128 X 64 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.
The frequency is displayed with leading zeros removed down to 3 digits. The font used is 5x7 pixels universal font. The period is calculated. When input frequency is less than 1000Hz the period is displayed in us.
The counting is over a period of 1 second divided from the 16 MHz crystal oscillator. The max counting is 6MHz (Atmel specs). Period of 1 sec is generated by the 3 internal timers.
Code is mostly in C and includes setting up the timers and counter, font 5x7 and oled initializing (no library for oled needed).

Counter using PIC16F628A. Included C code and circuit diagram. The OLED module is a 0.96" 128 X 64 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.
PIC16F628A uses software (bit banging) I2C.
The frequency is displayed with leading zeros removed down to 3 digits. The font used is 8x5 pixels universal font. The period is calculated. When input frequency is less than 1000Hz the period is displayed in us.
The counting is over a period of 1 second, divided from the 16 MHz crystal oscillator. The max counting is 7 digits (4MHz). Period of 1 sec is generated by TMR1 and CCP1.
Code is in MPLAB X and compilers  XC8 (ver1.45).

You are free to use the circuit diagram and the software with no limitations.

Counter using PIC16F876A. Included C code and circuit diagram. The OLED module is a 0.96" 128 X 64 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.
PIC16F876A drives the oled using hardware I2C.
The frequency is displayed with leading zeros removed down to 3 digits. The font used is 8x8 pixels universal font. The period is calculated. When input frequency is less than 1000Hz the period is displayed in us.
The counting is over a period of 1 second, divided from the 16 MHz crystal oscillator. The max counting is 7 digits (4MHz). Period of 1 sec is generated by TMR1 and CCP1.
Code is in MPLAB X and compilers  XC8 (ver1.45).