Class EpdIF
GTimerClass Class
Description
GTimer is a hardware timer and this class is to operate it. The GTimer
occupy same resource as PWM. Please make sure the timer is not
conflict with you PWM index.
Members
Public Constructors |
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GTimerClass::GTimerClass |
Constructs a GTimerClass object |
Public Methods |
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GTimerClass::begin |
Initialize a timer and start it immediately |
GTimerClass::stop |
Stop a specific timer |
GTimerClass::reload |
Reload a specific timer |
GTimerClass::read_us |
Read current countdown value |
GTimerClass::begin
Description
Initialize a timer and start it immediately.
Syntax
void GTimerClass::begin(uint32_t timerid, uint32_t duration_us, void (*handler)(uint32_t), bool periodical, uint32_t userdata);
Parameters
timerid: There are 5 valid GTimer with timer id 0~4.
duration_us: The duration of the timer. The time unit is microsecond
and the precision is 32768Hz.
periodical: By default, the timer would keep periodically countdown
and reload which means the handler would periodically be invoked.
userdate: The user data brings to the handler.
Returns
The function returns nothing.
Example Code
Example: TimerOneshot
/*
This sketch shows how to use several hardware timers in invoke handler
only once for each timer.
*/
#include <GTimer.h>
void myhandler(uint32_t data) {
Serial.print(“I am timer!”);
Serial.println(data);
}
void setup() {
// Open serial communications and wait for port to open:
Serial.begin(115200);
while (!Serial) {
; // wait for serial port to connect. Needed for native USB port only
}
// timerid 0, period 1s, invoke myhandler, invoke only once, user data
is 0
GTimer.begin(0, 1 * 1000 * 1000, myhandler, false, 0);
// timerid 1, period 2s, invoke myhandler, invoke only once, user data
is 1
GTimer.begin(1, 2 * 1000 * 1000, myhandler, false, 1);
GTimer.begin(2, 3 * 1000 * 1000, myhandler, false, 2);
GTimer.begin(3, 4 * 1000 * 1000, myhandler, false, 3);
}
void loop() {
delay(1000);
}
Example: TimerPeriodical
/*
This sketch shows how to use hardware timer and invoke interrupt handler
periodically
*/
#include <GTimer.h>
int counter = 0;
void myhandler(uint32_t data) {
counter++;
Serial.print(“counter: “);
Serial.println(counter);
if (counter >= 10) {
Serial.println(“stop timer”);
GTimer.stop(0);
}
}
void setup() {
// Open serial communications and wait for port to open:
Serial.begin(115200);
while (!Serial) {
; // wait for serial port to connect. Needed for native USB port only
}
// timerid 0, period 1s, invoke myhander
GTimer.begin(0, (1 * 1000 * 1000), myhandler);
}
void loop() {
delay(1000);
}
Notes and Warnings
Include “GTimer.h” to use the class function.
GTimerClass::stop
Description
Stop a specific timer
Syntax
void GTimerClass::stop(uint32_t timerid);
Parameters
timerid: Stop the timer with this timer id
Returns
The function returns nothing.
Example Code
Example: TimerPeriodical, please refer to GTimerClass:: begin for more
details.
Notes and Warnings
Include “GTimer.h” to use the class function.
GTimerClass::reload
Description
Reload a specific timer. The GTimer is a countdown timer. Reload it
would make it discard the current countdown value and restart
countdown based on the duration.
Syntax
void GTimerClass::reload(uint32_t timerid, uint32_t duration_us);
Parameters
timerid: The timer to be modified
duration_us: The updated duration in unit of microseconds
Returns
The function returns nothing.
Notes and Warnings
Include “GTimer.h” to use the class function.
GTimerClass::read_us
Description
Read the current countdown value
Syntax
uint64_t GTimerClass::read_us(uint32_t timerid);
Parameters
timerid: The timer to be read
Returns
The function returns the current countdown value.
Notes and Warnings
Include “GTimer.h” to use the class function.