You should declare as volatile any variables that you modify within the attached function.
#Arduino millis with interrupts serial#
Serial data received while in the function may be lost. Inside the attached function, delay() won’t work and the value returned by millis() will not increment.
The catch is your function is now part of an ISR (Interrupt Service Routine), and must be lean / mean, and follow certain rules. For example, certain function is blocking while it's connecting to WiFi or some services.
#Arduino millis with interrupts software#
That's necessary if you need to measure some data requiring better accuracy.įunctions using normal software timers, relying on loop() and calling millis(), won't work if the loop() or setup() is blocked by certain operation. Moreover, they are much more precise (certainly depending on clock frequency accuracy) than other software timers using millis() or micros(). These hardware timers, using interrupt, still work even if other functions are blocking. The correct choice is to use a Hardware Timer with Interrupt to call your function. You'd prefer to have your function called, no matter what happening with other functions (busy loop, bug, etc.). So your function might not be executed, and the result would be disastrous. But what if another function is blocking the loop() or setup(). You normally use a software timer to poll, or even place the function in loop(). Imagine you have a system with a mission-critical function, measuring water level and control the sump pump or doing something much more important. The elapsed time then is very unaccurate Why using ISR-based Hardware Timer Interrupt is better In loop(), using delay() function as an example. You'll see blynkTimer Software is blocked while system is connecting to WiFi / Internet / Blynk, as well as by blocking task This non-being-blocked important feature is absolutely necessary for mission-critical tasks. You can also have many (up to 16) timers to use. The ISR_16_Timers_Array_Complex example will demonstrate the nearly perfect accuracy compared to software timers by printing the actual elapsed millisecs of each type of timers.īeing ISR-based timers, their executions are not blocked by bad-behaving functions / tasks, such as connecting to WiFi, Internet and Blynk services. This important feature is absolutely necessary for mission-critical tasks. Therefore, their executions are not blocked by bad-behaving functions / tasks. The most important feature is they're ISR-based timers. Now with these new 16 ISR-based timers, the maximum interval is practically unlimited (limited only by unsigned long milliseconds) while the accuracy is nearly perfect compared to software timers. Timers' interval is very long ( ulong millisecs). This library enables you to use Interrupt from Hardware Timers on MBED RP2040-based boards such as Nano_RP2040_Connect, RASPBERRY_PI_PICO, using Arduino-mbed RP2040 coreĪs Hardware Timers are rare, and very precious assets of any board, this library now enables you to use up to 16 ISR-based Timers, while consuming only 1 Hardware Timer. Please have a look at HOWTO Fix Multiple Definitions Linker Error Why do we need this MBED_RPI_PICO_TimerInterrupt library Features ISR_16_Timers_Array_Complex on RaspberryPi Pico
ISR_Timers_Array_Simple on RaspberryPi Pico
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