ARDUINO MEGA 2560 TIMER PINS HOW TO
ARDUINO MEGA 2560 TIMER PINS CODE

TCCR2B = 0x05 //Timer2 Control Reg B: Timer Prescaler set to 128Ī few important things to note about the code: TCCR2A = 0x00 //Timer2 Control Reg A: Wave Gen Mode normal TIMSK2 = 0x01 //Timer2 INT Reg: Timer2 Overflow Interrupt Enable TCNT2 = 130 //Reset Timer Count to 130 out of 255 TCCR2B = 0x00 //Disbale Timer2 while we set it up TIFR2 = 0x00 //Timer2 INT Flag Reg: Clear Timer Overflow Flag TCNT2 = 130 //Reset Timer to 130 out of 255 Toggle = !toggle //toggles the LED stateĬount = 0 //Resets the interrupt counter Timer2 Overflow Interrupt Vector, called every 1msĬount++ //Increments the interrupt counter Unsigned int count = 0 //used to keep count of how many interrupts were fired Unsigned int toggle = 0 //used to keep the state of the LED one second) the LED on pin 53 will toggle. Timer2 is 8-bits so the max number it can count to is 255, this leaves 125 cycles left to count. The timer overflow interrupt fires every 1ms by setting the prescaler to 128 and preloading Timer2's counter with 130. This program will blink an LED on Port 53 once a second using a Timer2 Overflow Interrupt. By configuring the Timer2 Overflow Interrupt to fire every 1ms, we can increment a counter in the Interrupt Vector and wait until 1000 interrupts have occurred to toggle the LED. The following program can be used to replace the delay(1000) from the earlier project. When using the timers you need to check which pins they are connected to so that you know what functionality you are losing in regards to PWM. Looking at the Arduino schematic, the Timers are tied to the following Pins: I'll have to test this when I start messing with PWM. But, if I read the schematic correctly, it appears there are possibly three more pins PWM ready: Pins 44, 45, and 46. The Arduino website says the Mega2560 has 14 PWM pins available. Using a timer for an interrupt will interfere with using the pins it's tied to for PWM. The tricky part is that they are already tied to specific peripherals and functions. There are a six available timers in the Arduino Mega.

One simple way to get around using the delay function is to use timers instead.

ARDUINO MEGA 2560 TIMER PINS CODE

Using the function locks up the processor and prevents any other code from running until it is done waiting. If you read the previous blog post you might remember the problem I mentioned when using the delay function.

ARDUINO MEGA 2560 TIMER PINS HOW TO

Anybody can open up the example code and make an LED blink, but do you know how to do this with timers and interrupts? It's important to know your microprocessor fundamentals or you're going to be spending a lot of time on the forums and wading through Google searches.

Arduino mega 2560 timer pins