![]() ![]() Thus, a good way of implementing interrupt handling code is making the ISR only signal the occurrence of the interrupt and defere the actual handling (which may contain operations that take a while) to the main loop. We have seen this use of a counter in the previous tutorial about external interrupts because, as explained, ISRs should run as fast as possible and should not perform long operations, such as writing to the serial port. The first one will be a counter that will be used by the interrupt service routine to signal the main loop that an interrupt has occurred. We start our code by declaring some global variables. The value of the counter can be read by the software program. They can also generate alarms when they reach a specific value, defined by the software. The timer counters can be configured to count up or down and support automatic reload and software reload. Since the prescaler has 16 bits, it can divide the clock signal frequency by a factor from 2 to 65536, giving a lot of configuration freedom. The prescaler is used to divide the frequency of the base signal (usually 80 MHz), which is then used to increment / decrement the timer counter. All the timers are based on 64 bits counters and 16 bit prescalers. The ESP32 has two timer groups, each one with two general purpose hardware timers. The tests were performed on a DFRobot’s ESP-WROOM-32 device integrated in a ESP32 FireBeetle board. ![]() So, in this tutorial, we will check how to configure the timer to periodically generate an interrupt and how handle it. ![]() The code shown here is based on this example from the Arduino core libraries, which I encourage you to try. The objective of this post is to explain how to configure timer interrupts on the ESP32, using the Arduino core. ![]()
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