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121 lines
4.1 KiB
Markdown
121 lines
4.1 KiB
Markdown
[](https://github.com/marketplace/actions/arduino_ci)
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[](https://github.com/RobTillaart/timing/actions/workflows/arduino-lint.yml)
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[](https://github.com/RobTillaart/timing/actions/workflows/jsoncheck.yml)
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[](https://github.com/RobTillaart/timing/blob/master/LICENSE)
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[](https://github.com/RobTillaart/timing/releases)
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# Timing
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Arduino library with wrappers for seconds, millis, and micros.
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## Description
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A request often made on the Arduino forum and otherwise is an option to reset
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the **millis()** function to 0 or to another value.
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This library provide wrapper classes around **millis()** and **micros()**
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with the extra function to do reset the count by means of an offset.
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To implement this only a 4 byte offset is needed per "clock".
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The classes are based upon **millis()** and **micros()**.
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Therefore they have the same restrictions as these functions with respect to
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overflow and accuracy. Depending on e.g. interrupts, millis() and micros() can drift.
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| class | overflow after | Notes |
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|:---------------|:---------------------------|:----------------------|
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| seconds | 49 days, 17:02:47 | based upon millis() |
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| milliSeconds | 49 days, 17:02:47.297 | based upon millis() |
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| microSeconds | 00 days 01:11:34.967296 | based upon micros() |
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#### Tests
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Code is tested on UNO and ESP32, should work on all platforms.
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No performance tests as code is 'basic'.
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## Applications
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These classes make it easy to make a simple stopwatch, clock or countdown timer.
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It is also possible to sync the time (e.g. millis()) with an external source,
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which could be another Arduino.
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## Interface
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```cpp
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#include "timing.h"
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```
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The interface of all three are very similar:
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- **microSeconds()** constructor, sets the offset so it starts at 0.
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- **milliSeconds()** constructor, sets the offset so it starts at 0.
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- **seconds()** constructor, sets the offset so it starts at 0.
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- **uint32_t now()** returns the time elapsed since its 'zero moment'.
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Ether set during construction or by a call to **set(0)**.
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- **void set(uint32_t value = 0UL)** sets the offset of the object.
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As it is possible to set it to a non zero value it is easy to adjust the time.
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This allows one e.g. to compensate for overhead. Default = zero.
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- **void add(uint32_t value)** allows one to increment or decrement the offset for calibration.
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Allows one to sync time e.g. with an external reference in small incremental steps.
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- **uint32_t getOffset()** returns current offset in base units.
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So seconds for seconds, millis for millis and micros for micros.
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- **double toSeconds()** returns a float representation of the current value in seconds.
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e.g. 15678 milliseconds becomes 15.678 seconds (SI units).
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#### Experimental
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- ** char \* toClock()** converts current seconds to a clock like char array "HH:MM:SS".
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Only for the seconds class for now.
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## Future
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#### Must
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- update documentation
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- describe rounding effect (seconds)
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#### Should
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- implement toClock()
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- seconds.toClock() -> DD 12:34:56 (days ??)
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- milliSeconds.toClock(3) -> 12:23:45.123 (3) == 3 decimals..
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- milliSeconds.toClock(1) -> 12:23:45.1
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- microSeconds.toCLock() -> 12:23:45.123456 ???
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- printHelpers class?
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```cpp
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// something like this.
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char * toClock()
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{
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static char buf[12];
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uint32_t _now = now();
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int hh = _now / 3600;
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_now = _now - hh * 3600;
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int mm = _now / 60;
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int ss = _now - mm * 60;
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sprintf(buf, "%02d:%02d:%02d", hh, mm, ss);
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return buf;
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}
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```
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#### Could
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- nanos() on ESP32 ?
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- measureable?
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- implement printable interface
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- add unit (s, ms, us)
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- what layout to use?
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- move code to .cpp file?
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#### Wont
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