![]() So far, I have tested this library on an Uno and a Mega. There are many tutorials on how the prescaler affects timers and this library contains methods that make easier and less bug prone to manipulate. If you don't want to sacrifice any 8bit PWM pins, don't call the initialize function for that timer, try changing the prescaler to manipulate frequency instead. To be sure the frequency was correctly set, be sure to check the return value. It is technically possible to push the frequency to 8MHz, but the range of possible power duties get stupidly small by that point. As the frequency becomes larger, the smaller the range power duties for a pin becomes. 8bit timers have a range from 31Hz to 2MHz. With this Library, 16bit timers have a frequency range from 1Hz to 2MHz. The global ones should be good enough for most situations. It is up to your discretion whether or not you want to use the timer specific functions. If you want to mess with a different timer, just change the number (i.e Timer2_GetFrequency() to get timer 2's frequency). ![]() If those give a type error, then the timer you are using is one of the inconsistent ones, and you should use psalt_1, psalt_8, psalt_32, psalt_64, psalt_128, psalt_256, or psalt_1024 instead. For a normal timer, use one of these as a parameter: ps_1, ps_8, ps_64, ps_256, ps_1024. I figured using enumerators was the best solution because most types of invalid input will be caught at compile time. *The prescaler is inconsistent among different timers. Don't know what this means? Don't worry about it, just use SetFrequency(int frequency) Gets the value (not bits) of the prescaler. Each of these functions are technically preprocessor macros with nice self explanatory names that swap out for more cryptic functions inside the library header just before compile time. Diptrace Arduino Libraries code#I could not get the code size down to what I felt was reasonable so I ditched C++ classes and did some fancy macro work instead. The library also has five functions for each Timer 'object'. Same as SetPinFrequency except it does not affect timer 0 SetPinFrequencySafe(int8_t pin, int32_t frequency) Sets the pin's frequency (in Hz) and returns a bool for success SetPinFrequency(int8_t pin, int32_t frequency) Continue to use analogWrite() on uninitialized timers Same as 'analogWrite()', but it only works with initialized timers. Same as InitTimers() except timer 0 is not initialized in order to preserve time keeping functions Needs to be called before changing the timers frequency or setting the duty on a pin Regardless of this, I still felt it would still be worth while to make a library/wrapper for hardware timers so that I, and anyone else who chooses to use this, will not have to spend quite as many hours needlessly digging through blocks of bug prone bit wise and preprocessor slurry. All Arduinos except the Leonardo have two 8bit timers, meaning that setting all timers to a particular frequency will sacrifice a total of two pins on said Ardiuno. In other words, each 8bit timer that creates a custom frequency loses the ability to perform PWM on one pin (the one connected to the A channel to be more precise). Creating custom frequencies (beyond messing with the prescaler) with an 8bit timer requires the sacrifice of one channel.Long story short, they have nuances that make common code difficult to implement without limiting one or the other. There are two types of timer, 8bit and 16bit.Changing the frequency on timer 0 will break the time keeping functions you may or may not be using in other parts of your project Timer 0 is usually used for Arduino's time keeping functions, (i.e.Which in turn changes the frequency of other pins connected to that same timer. Changing one pin's frequency requires changes to the timer it connects to. PWM behavior is determined by integrated components called timers.The hardware is has very specific limitations that present themselves in odd ways. It is my speculation that the programmers at Arduino have not released any methods for changing PWM frequency because it is difficult to write a simple and intuitive wrapper for hardware timers that wont run the risk of confusing a beginner (the whole draw to Arduino in the first place). Diptrace Arduino Libraries full#The internet is full of partial examples and code snippets for changing PWM frequency, but in the end I still had to consult the 400+ page sec sheet ( Smart | Connected | Secure | Microchip Technology) to get the code for my Mega functional. As far as I can Google, there is no general purpose library that can change PWM frequencies on Arduino Microcontrollers. ![]() I discovered in a recent project involving an Arduino microcontroller that there was no method to change PWM frequency without directly manipulating low-level memory. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |