I have an encoder that was connected to my ESP32 and working great, because im running out of pins I move them to PCF8575 module but I cant read the value of INPUT pin. What is strange is that by using Wire.h library I can see that values changes so the module is working fine the problem is the library.
#include "Arduino.h"
#include "PCF8575.h"
// Set i2c address
PCF8575 pcf8575(0x20, 21,22);
void setup()
{
Serial.begin(115200);
pcf8575.pinMode(P2, INPUT);
pcf8575.begin();
}
void loop()
{
byte di = pcf8575.digitalReadAll();
Serial.print("READ VALUE FROM PCF: ");
Serial.println(di, BIN);
delay(50);
}
Any clue? I always get 00000000 and when I press the encoder button I dont see anything change in the byte. And as I said by using Wire I can see that the corresponding bit changes.
This is my code using Wire.h
#include "Arduino.h"
#include <Wire.h>
#define pcf8575adress 0x20
void setup()
{
Serial.begin(9600);
Wire.begin();
pf575_write(word(B11111111,B11111111));
}
void loop()
{
Wire.requestFrom(pcf8575adress, 1);
byte incomingByte = Wire.read();
printBinary(incomingByte);
//Serial.println(incomingByte, BIN);
delay(500);
}
void printBinary(byte b) {
for (int i = 7; i >= 0; i-- )
{
Serial.print((b >> i) & 0X01);//shift and select first bit
}
Serial.println();
}
// Function for writing two Bytes to the I2C expander device
void pf575_write(uint16_t data)
{
Wire.beginTransmission(pcf8575adress);
Wire.write(lowByte(data));
Wire.write(highByte(data));
Wire.endTransmission();
}
I found an issue and is related to setting pinMode. I was debugging the .cpp file and when setting pinMode then when wire reads the value the byte returns 0000000, if manually on other arduino project I set wire write to all pins to OUTPUT 111111111111111 then I I upload the library code again I can see that wire read now works.
Hi Alejandro,
I think the problem is the debounce time and setting; if an input pin goes up then goes down in the interval, you lost the change.
Try to set
#define READ_ELAPSED_TIME 10
To 0 so you remove debounce, and you must use interrupt.
Maintaining a repository (or site or forum) is a lot like tending to a garden - it requires constant care and attention to keep it thriving. If you're a skilled gardener (or coder!) and want to help keep our repository blooming, we'd love to have you on board! We're also looking for talented writers and forum moderators to help us grow our community. Interested in joining our team? Don't hesitate to reach out and let us know how you can contribute!
Are you a fan of electronics or programming? Share your knowledge with others, write a simple tutorial or how to make a great project Contact me: share_your_ideas@mischianti.org