Universal Frequency Counter

The project is based on Lattice ispLSI2032 PLD and AT90S8515 microcontroller to create a universal frequency counter that has the ability to communicate with PC via serial port.

In the design, the PLD counts incoming pulses and scales them down due to the implementation of 36-bit hardware counter while the microcontroller handles communication and data display. An interrupt for MCU is generated when the counter counts up. The counter can log data to computer or be controlled by computer.

The microcontroller AT90S8515 was chosen because they are not that complex which makes them easy to use compared to other microcontroller. The most important block in this universal frequency counter is the main counter which is divided into PLD and MCU. The PLD part is a 12-bit counter that can count up to 4096 and its most significant bit is connected to an external interrupt pin of the MCU.

The measured value is collected by available communication interface where any process is applied with a PC. The communication interface must be isolated from its system ground since this universal counter is a measurement instrument. The interface is compatible serial port, isolated with optical sensors.

Rest of the project