#Arduino timer interrupt driven loop for free
#Arduino timer interrupt driven loop code
#Arduino timer interrupt driven loop plus

when the DRIVERPIN switch from HIGH to LOW, it means the timer is expired, thus time to trigger ISRĪttachInterrupt(digitalPinToInterrupt(drv_pin), do_smth, mode)

#Arduino timer interrupt driven loop plus

This might work better since every function call takes at minimum 8 cycles (might have been 6, memory is a bit fuzzy on this particular detail) PLUS all the stack PUSH'n an' POP'n, which depends on your variable usage.// reset tpl5110 timer for an another round

#Arduino timer interrupt driven loop code

If the slower running rate looks visually unpleasant you can of course try to reduce the prescaler and OCR1A, but you should also consider dispensing the ISR's altogether and just run your led flashing code in the main loop and have just the ADC ISR acquire data to be processed.

Keep in mind that the human eye cannot detect insanely fast flickering (hence pwm driven leds work as they do, with no visible flicker). Common performance hogs are, for example, frequent data fetches from SRAM, but if you're using gcc you might find all sorts if groovy stuff happening upon ISR entry. If you want to squeeze every last drop of performance out of the old 328 you should inspect the generated assembly for your interrupt routines, and figure out if you can do something to optimize them. An easy solution is to increase the count in OCR1A to, say, 5 and increase the prescaler of the ADC ADCSRA |= (1 << ADPS1) // ADC prescaler 8, conversion time 4*26 MCU cycles You basically use all your time acquiring data and/or in your timer ISR. On top of that, your TIMER1_COMPA ISR is also fired so frequently (every 64 cycles) that your ISR might actually take longer to execute than the desired time.

This means that your ADC ISR is firing every 26 clock cycles with your current prescaler settings.

#Arduino timer interrupt driven loop for free

In Free Running mode, a new conversion will be started immediately after the conversion com-Īnd the conversion time for free running mode (on table 23-1, page 255) is specified as 13 ADC clock cycles. One thing that I notice from your code is that you are acquiring the samples in free running mode with ADC clock at F_CPU/2. In the mainloop I just try to set some leds but it doesn't work. The ADC interrupt is triggered everytime a value from A0 is ready. shift timer compare and set timer back to generate delay (Bit Angle Modulation)īitSet(PORTB, ledPORTB) //set pin 12 highīitClear(PORTB, ledPORTB) //set pin 12 low

The timer and the ADC are initialzed like this: cli() //stop all interrupts īoth impementations work alone but when I try to bring the code together it breaks. To achieve fast frequency detection I use a technique described here. Now I want to influence the color of the leds by measuring sound frequencies with an Electret microphone breakout board. The Leds are controlled by 4 74hc595 shiftregisters.īasically I shift out the bits to control the really fast during a timer interrupt. I soldered a 6x8 RGB Led Matrix and use binary coded modulation to mix the colors. I'm a programmer and not jet experienced with arduino or any microcontrollers.