Differences

This shows you the differences between two versions of the page.

--- en-us_commands:reference:itimerstart [2026/09/08 00:53] – 바깥 편집 127.0.0.1
+++ en-us_commands:reference:itimerstart [2026/10/25 08:41] (current) – external edit 127.0.0.1
@@ Line 15: / Line 15: @@
 ===== Example =====
+This uses the default callback timer (Timer2). The callback changes only a flag; serial output runs in ''loop()''.
 <code cpp>
@@ Line 24: / Line 26: @@
 void setup() {
-  pinMode(13, OUTPUT);
+  Serial.begin(115200);
-  ItimerSet(1000, onTimer);  // Set the interval and callback function, or select the hardware timer to use.
+  if (!ItimerSet(1000, onTimer)) return;  // Configure the callback and interval first.
-  ItimerStart();  // Start the configured callback timer.
+  if (!ItimerStart()) return;  // Start the configured default callback timer.
 }
 void loop() {
   if (tick) {
+    noInterrupts();
     tick = false;
-    digitalWrite(13, !digitalRead(13));
+    interrupts();
+    Serial.println(F("tick"));
   }
 }
@@ Line 39: / Line 43: @@
 ===== Precautions =====
-  * Timer interrupt callbacks run inside an ISR. For safety, change only flags in the callback and perform actual control processing in ''loop()''.
+  * The callback runs in an interrupt. Change only a flag there; do not call ''delay()'', ''Serial'', I2C or SPI in it.
-  * Do not use slow or interrupt-dependent code such as ''delay()'', ''Serial'', I2C or SPI in callbacks.
+  * The callback timer without a timer number uses Timer2. Do not use it together with ''tone()'' or PWM output that uses Timer2.
-  * Normally, call ''ImodbusRTU()'' repeatedly in ''loop()''. Call it from a timer interrupt with a sufficient interval only when long ''delay()'' calls or debug output slow down ''loop()''.
+  * When specifying another hardware timer, check for conflicts with PWM, analog output and high-speed counter functions using it.
-  * Do not use the default ''ItimerSet()'' together with ''tone()'' using Timer2 or ''analogWrite()'' on Timer2 PWM pins.
+  * Starting before ''ItimerSet()'' has configured the timer returns false.
-  * Explicitly using Timer1, Timer3, Timer4 or Timer5 may conflict with PWM, analog output or high-speed counter functions using that timer.
-  * Configure only one ''Itimer'' callback per hardware timer.
-  * Defining an ISR for the same timer directly in the sketch may conflict with ''Itimer'' operation.
-  * ''ItimerStopAll()'' stops only hardware interrupt timers. It does not reset PLC-style timer states such as ''Iton'', ''Itof'' or ''Itmr''.
 ===== Built-in Commands in the Same Category =====
-  * [[:en-us_commands:reference:itimerset|ItimerSet() View detailed description]]
+  * [[:en-us_commands:reference:itimerset|ItimerSet() reference]]
-  * [[:en-us_commands:reference:itimerstop|ItimerStop() View detailed description]]
+  * [[:en-us_commands:reference:itimerstop|ItimerStop() reference]]
-  * [[:en-us_commands:reference:itimerstopall|ItimerStopAll() View detailed description]]
+  * [[:en-us_commands:reference:itimerstopall|ItimerStopAll() reference]]
-  * [[:en-us_commands:reference:itimerstate|ItimerState() View detailed description]]
+  * [[:en-us_commands:reference:itimerstate|ItimerState() reference]]
 [[:en-us_commands:builtin|← Built-in Command List]]