![]() You could get the timer to run at the full 16MHz (62.5nSec) though that's way faster than you need 2MHz with an initial count of (255-2) would give you 1MHz interrupt rate.First, you need to record the time at which the action took place then check continuously whether the required period has elapsed. Blocking these functions from running can cause the ESP8266 to crash and reset itself. The ESP8266 runs a lot of utility functions in the background keeping WiFi connected, managing the TCP/IP stack, and performing other duties. Given this information, the resulting interrupt rate would be: This is one of the most critical differences between the ESP8266 and a more classical Arduino microcontroller. Therefore, your sketch should use timer1 (16-bit) or timer2 (8-bit). This MCU has three timers, and the delay(), millis(), and micros() functions use timer0. In this example, I use the ATMega328PU that comes on the classic Arduino Uno board. This interrupt is called TIMER2_OVF_vect. The timers on the Arduino use the board’s internal 16MHz crystal oscillator. When the counter reaches the value assigned by TCNT2 it triggers an interrupt. The code is working perfectly with one lamp/pot. I need simultaneously readings from multiple potentiometers. Code samples in the reference are released into the public domain. The text of the Arduino reference is licensed under a Creative Commons Attribution-ShareAlike 3.0 License. I need to get rid off delays cuz the readings cant be late. Corrections, suggestions, and new documentation should be posted to the Forum. ![]() There is build in counter that goes from 0 to 255 because the timer is 8 bit. The delayMicroseconds () wont let me control multiple lamps, so I want to replace it with micros () (code below). The timer has built in "prescaler" value options which determine frequency/period, shown in this table: TCCR2B bits 2-0 Prescaler Freq, Period after prescaleįor better timing resolution, you use a value called TCNT2. For example here are the counter-timer input frequencies and periods after pre-scaling, for an ATMega2560's counter-timer 2, and a basic clock rate of 16MHz. Can be handy for testing purposes, but you do not need this to handle the millis () rollover problem. timer overflow, serial, others) may execute before the delayMicroseconds function returns and thus upset precise timing. SofwareSerial bit banging) by disabling interrupts during its core delay code. On the boards from the Arduino Portenta family this function has a resolution of one microsecond on all cores. The delayMicroseconds () function will provide accurate delays as may be needed for some types of applications (e.g. This number will overflow (go back to zero), after approximately 70 minutes. The liked answer also gives the trick for resetting millis (). Description Returns the number of microseconds since the Arduino board began running the current program. ![]() However, this is not a problem: as long as you compare durations instead of timestamps you can forget about the overflows. Certain things do go on while the delay () function is controlling the Atmega chip, however, because the delay function does not disable interrupts. millis () and micros () overflow periodically. Yes, depending your Arduino's basic clock rate. More knowledgeable programmers usually avoid the use of delay() for timing of events longer than 10s of milliseconds unless the Arduino sketch is very simple.
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