read()
Description
Function to read the encoder’s counter value and pulse width.
Note: Under different mode, the return value has different representation. See the Returns section below.
Syntax
Enc0.read()
Enc1.read()
Enc2.read()
Enc3.read()
Parameters
Enc0、Enc1、Enc2、Enc3：Corresponding to ENC0, ENC1, ENC2 and ENC3 encoder interfaces.
Returns
Pulse/DIR, CW/CCW and A/B Pulse modes: Return the encoder’s counter value.
PWM pulse capture mode: Return the pulse width value for digital HIGH or LOW condition in micro-second (us), where the maximum value is 71 minutes. (Note: Under this mode, the read() function can only be called within an associated ISR function. When using this function elsewhere, it always return 0.)
SSI mode: Return SSI absolute value from the encoder.
Example
Set ENCO to A/B Pulse mode, and read the encoder’s counter value.
#include <Encoder.h>
void setup() {
Serial.begin(9600);
Enc0.begin(MODE_AB_PHASE);
}
void loop() {
Serial.println(Enc0.read());// Read encoder counter value
delay(100);
}
Set ENC1 to PWM pulse capture mode, read the pulse width for digital HIGH and LOW condition.
#include <Encoder.h>
volatile unsigned long num1 = 0L;
volatile unsigned long num2 = 0L;
void encoder_isr(int flag) { // ISR function
if (flag == INTR_A_PULSE_LOW)// Read pulse width during digital LOW condition
num1 = Enc1.read();
else if (flag == INTR_A_PULSE_HIGH) // Read pulse width during digital HIGH condition
num2 = Enc1.read();
}
void setup() {
Serial.begin(9600);
Enc1.begin(MODE_CAPTURE);
Enc1.attachInterrupt(encoder_isr);// Mount ISR function and enable interrupt
}
void loop() {
Serial.print("LOW:");
Serial.print(num1); // Output pulse width during digital LOW condition in micro-second (us)
Serial.print(" ");
Serial.print("HIGH:");
Serial.println(num2); // Output pulse width during digital HIGH condition in micro-second (us)
delay(100);
}
See also
－ attachInterrupt()
The text of the 86Duino reference is licensed under a Creative Commons Attribution-ShareAlike 3.0 License. Code samples in the reference are released into the public domain.
