Hardware timers
The ESP8266 has one of these, HardwareTimer, which can be programmed to trigger
when a pre-programmed interval has elapsed. The callback handler is executed in an
interrupt context so is restricted on what it can do.
The timer is appropriate where accurate and short timing is required.
The API for hardware (and Software timer queues timers) is identical, implemented using a
CallbackTimer class template for best performance.
Note
Applies to Esp8266 architecture only.
As with all Callback timers, the HardwareTimer can be one-shot or repeating.
With the Esp8266 a one-shot timer will repeat after it has been triggered, but only after the timer counter wraps around. The Esp8266 only has 23 bits of resolution so with a clock divider of 16 this will happen after about 1.7s.
Because the Esp8266 lacks any proper PWM hardware the timer latency is critical. Adding any additional code to the callback is therefore left to the programmer.
- group hardware_timer
Hardware callback timer.
Typedefs
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template<hw_timer_clkdiv_t clkdiv = TIMER_CLKDIV_16, HardwareTimerMode mode = eHWT_NonMaskable>
using HardwareTimer1 = CallbackTimer<Timer1Api<clkdiv, mode>> Hardware Timer class template with selectable divider and interrupt mode.
-
using HardwareTimer = HardwareTimer1<>
Default hardware Timer class.
Enums
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template<hw_timer_clkdiv_t clkdiv, HardwareTimerMode mode>
class Timer1Api : public CallbackTimerApi<Timer1Api<clkdiv, mode>> - #include <HardwareTimer.h>
Class template for Timer1 API.
Note
Provides low-level interface for timer access
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template<hw_timer_clkdiv_t clkdiv = TIMER_CLKDIV_16, HardwareTimerMode mode = eHWT_NonMaskable>