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How does the PIC16F84A Blink without delay interrupt?
PIC16F84A blink without delay (Timer0 interrupt) The microcontroller PIC16F84A has 1 timer which is Timer0, this timer has a resolution of 8 bits and an interrupt-on-overflow from FFh to 00h. This topic shows how to use Timer0 interrupt to blink an LED. This interrupt is generated when the TMR0 register overflows from FFh to 00h.
What are the features of the PIC16F84A microcontroller?
Timer: PIC16F84a contains one 8-bit timer that can be utilized in both ways i.e. timer and counter. Furthermore, accompanies internal and external clock select capability. Sleep Mode: This mode is included the chip that produces a low current power down mode.
How are interrupts setup in a PIC microcontroller?
Fig. 1 PIC1684A interrupt map. The Microchip PIC series of microcontrollers have several sources of hardware interrupts. These are RISC microcontrollers with 35 instructions. To configure interrupts or other hardware functions are setup by configuring various bits in selected registers, in particular here the INTCOM register.
When to call the ISR routine PIC16F84A?
Fig. 3 PIC16F84A Memory Map. Above is a sample ISR routine called when a switch was pressed on say PB7.
How does a timer work in a timer overflow interrupt?
Every time we have a clock cycle – the time between two adjacent pulses of the main oscillator – the counter increases according to the prescaler set for those timer. The prescaler is used to reduce a high frequency counter to a lower frequency by integer division.
Which is the clock source for timer0 in CCS?
The clock source can be internal or external through RA4/T0CKI pin. Prescaler rate of Timer0 can be: 2, 4, 8, 16, 32, 64, 128 or 256. The clock source and prescaler can be set using the following CCS command: where TMR0 is Timer0 preload value. and: peroid = 1/Timer0_freq which is time to interrupt.
How is the timer in a microcontroller set?
So take a look on the Datasheet of this specific microcontroller. You can see that the Timer 1 – called Timer/Counter 1 – can be set by the TCCR1B register. It this specific case, Timer 1 is a 16 bit timer, this means that the maximum timer value is 65536. “The bits 2:0 select the clock source to be used by the Timer/Counter”.