Implement HardwareTimer library for Timer management

[fpistm]

This issue is to open discussion around Timer management in order to provide useful API.
Current implementation is limited to support basic Arduino function.
Any help/comment are welcome.

[Adminius]

I need this feature:
https://github.com/rogerclarkmelbourne/Arduino_STM32/blob/master/STM32F1/libraries/A_STM32_Examples/examples/Maple/TimerInterrupts/TimerInterrupts.ino#L35

Something like this, but user friendly: https://github.com/adafruit/Adafruit_ZeroTimer/

Edit @fpistm: Add #104 request here.

[romainreignier]

On AVR, I usually use this library, the API is simple enough: https://www.pjrc.com/teensy/td_libs_TimerOne.html

But it only allows to use timers for interrupt callback. You cannot configure a timer as quadrature encoder counter from it for example.

[Adminius]

Timer1 and Timer3 are good libs!
This one too: https://github.com/wimleers/flexitimer2

[Adminius]

My requirements:

1. Interrupt driven function call with resolution: 1us, 1ms, 1s.
2. better PWM generation: flexible PWM frequency, flexible counter, up-up/up-down (e.g. https://github.com/Adminius/Dimmer32u4)

[franciscogimeno2000]

Someone knows why libraries do not work
Timer1 ... 2 ... flexitimer2 in board STMF303 - F303K8

[fpistm]

@franciscogimeno2000 simply because not ported for stm32. Ex Flexitimer uses direct register acces but this is not the same for stm32.
Goal of this issue is to collect requirements/proposal/API examples... to implement timers management useful for community.
Any contributions are welcom 😉

[franciscogimeno2000]

OK, you have some example of using a basic timer.?

[straccio]

For my projects i usually use particle boards, the are also based on STM32.
Take a look on their Software Timer https://docs.particle.io/reference/firmware/photon/#software-timers

They use Free RTOS, also available for more stm32 boards, but if you don't want use Free RTOS can you use the same interface for class.

PS: remember to use also std::function as callback.

[marcdepape]

I have a NUCLEO F1 and F4 and spent the weekend trying to use timer.h / timer.c with them. It was a struggle.

For example (I'm going to truncate my code, and I don't have to use timer_enable_clock(_timer.handle); because I tried, and as far as I can tell it is called by these Inits), this does not work:

stimer_t _timer;
TimerHandleInit(&_timer, 100000, 384);
attachIntHandle(&_timer, handle_clock);

Yet, this does:

stimer_t _timer;
TimerPulseInit(&_timer, 500, 40000, pulse_clock);
TimerHandleInit(&_timer, 100000, 384);

In my callback I blinked an led and I used the following to debug after initializing:

Serial.println(getTimerIrq(_timer.handle.Instance)); Serial.println(getTimerClkSrc(_timer.handle.Instance)); Serial.println(getTimerClkFreq(_timer.handle.Instance));

In the first example I got: 0, 0, 0
In the second example I got: 28, 1, 84000000

From looking through the code, the TimerPulseInit actually assigns a timer:

obj->timer = TIMER_SERVO;

Whereas TimerHandleInit does not assign a timer.

In fact, I couldn't figure out for the life of me how to assign a specific timer to either of these functions, however I tried _timer.timer = TIM2; and it worked:

stimer_t _timer;
_timer.timer = TIM2;
TimerHandleInit(&_timer, 100000, 384);
attachIntHandle(&_timer, handle_clock);

Can I suggest the following:

1. You should be able to assign a timer when you declare your stimer_t obj:

stimer_t _timer(TIM8);

2. You should be able to assign a callback to TimerHandleInit:

void TimerHandleInit(stimer_t *obj, uint16_t period, uint16_t prescaler, void (*irqHandle)(stimer_t *))

This would greatly simplify everything. I think this is almost there, and the efforts to simplify the setup are good so far... just needs a bit of polish.