Timer0 .. 4

Timers, PWM (mwx::periph_timer)

The timer has two functions: to generate a software interrupt at a specified period, and to output a PWM at a specified period. 5 timers in total are available in the TWELITE radio module, from 0...4.

The name of the built-in object is Timer0..4, but will be referred to as TimerX on this page.

Methods

setup()

void setup()

Initializes the timer. This call allocates the necessary memory space.

begin()

void begin(uint16_t u16Hz, bool b_sw_int = true, bool b_pwm_out = false)

Starts a timer; the first parameter is the period of the timer in Hz; setting the second parameter to true enables software interrupts; setting the third parameter to true true` enables PWM output.

You can change the frequency with change_hz(). The change_hz() allows more detailed specification than the begin() specification.

The duty ratio of PWM output can be changed with change_duty().

To describe the processing of the interrupt handler, specify it in the application behavior definition.

end()

void end()

Stops the timer operation.

available()

inline bool available()

It becomes true at loop() immediately after a timer interrupt occurs, and becomes false when loop() ends.

change_duty()

void change_duty(uint16_t duty, uint16_t duty_max = 1024)

Set the duty ratio. the first parameter specifies the duty ratio (a small value makes the average of the waveform closer to the GND level, a large value makes it closer to the Vcc level). the second parameter specifies the maximum duty ratio value of the duty ratio.

It is recommended that duty_max be one of 1024,4096,16384.

The internal calculation of the count value involves division, but only for these three values is bit shifting used, while for other values, a computationally expensive division process is performed.

change_hz()

void change_hz(uint16_t hz, uint16_t mil = 0) 

Sets the frequency of the timer; the second parameter is an integer with three decimal places for the frequency. For example, to set the frequency to 10.4 Hz, specify hz=10, mil=400.