To generate a square wave of 50Hz with a 75% duty cycle through P1.2 of an 8051 microcontroller, you can use the Timer/Counter feature of the microcontroller. Here's a step-by-step guide:
Configure the Timer/Counter in Mode 1 (16-bit Timer) on the 8051 microcontroller. This mode allows you to generate square waves by utilizing Timer 1.
Calculate the timer period required for a 50Hz frequency. The timer period can be calculated using the formula:
Timer Period = (1 / Frequency) * (Timer Clock Frequency)
Assuming a crystal oscillator frequency of 12MHz for the 8051 microcontroller, the timer period can be calculated as follows:
Timer Period = (1 / 50) * (12 MHz) = 240,000 cycles
Determine the number of cycles for the ON phase of the square wave to achieve a 75% duty cycle. Since the duty cycle is 75%, the ON time would be 75% of the timer period:
ON Cycles = Duty Cycle * Timer Period = 0.75 * 240,000 = 180,000 cycles
Load the timer with the initial count value required for the ON phase. Subtract the ON cycles from the timer period and load it into the Timer 1 registers (TH1 and TL1) of the 8051 microcontroller.
Set up the interrupt service routine (ISR) to toggle P1.2 when the timer overflows.
Enable the Timer 1 interrupt and start the timer.
With these steps, the microcontroller will generate a square wave of 50Hz with a 75% duty cycle through P1.2.
Note: The specific instructions and syntax may vary depending on the assembler or compiler used for programming the 8051 microcontroller. Please refer to the documentation or user manual of your specific microcontroller and development tools for detailed implementation guidance.