dimitre
Well-known member
I'm trying to use the PCF8574P port expander with Teensy 3.2 but I can't receive the transmission yet.
I'm posting the wiring and the code.
interrupt seems to be working, but no transmission yet.
If I use pullup resistors in i2c ports the interrupt stops working.
I've tried different chips, different teensies and checked continuity for all connections.
Tried a i2c port scanner too and it doesn't find i2c device in any address.
Ideas are very welcome
and scanner code
I'm posting the wiring and the code.
interrupt seems to be working, but no transmission yet.
If I use pullup resistors in i2c ports the interrupt stops working.
I've tried different chips, different teensies and checked continuity for all connections.
Tried a i2c port scanner too and it doesn't find i2c device in any address.
Ideas are very welcome
Code:
//PCF8574P
#include <Wire.h>
//Thanks for your help, my IC is a PCF8574AF, so the correct address was 0x38 (decimal 56)
//B00100000 //B00111000
#define EXPANDER 0x20 //expander address
void setup() {
Serial.begin(9600);
Wire.begin();
delay(300);
expanderWrite(B11111111);
attachInterrupt(5, expanderInterrupt, CHANGE);
Serial.println("begin ");
Serial.println(EXPANDER);
}
void loop() {
Wire.requestFrom(EXPANDER, 1);
if (Wire.available()) {
byte _data = Wire.read();
Serial.print("DATA :: ");
Serial.println(_data, BIN);
Serial.println(_data, BIN);
Serial.println(_data);
byte inpBuff = _data & 0x01;
Serial.println(inpBuff, HEX);
}
}
void expanderInterrupt() {
Serial.print("interrupt :: ");
Wire.requestFrom(EXPANDER, 1);
if (Wire.available()) {
byte _data = 0;
_data = Wire.read();
Serial.print("DATA :: ");
Serial.println(_data, BIN);
Serial.println(_data, BIN);
Serial.println(_data);
byte inpBuff = _data & 0x01;
Serial.println(inpBuff, HEX);
}
Serial.println("------------------------");
}
void expanderWrite(byte _data ) {
Wire.beginTransmission(EXPANDER);
Wire.write(_data);
Wire.endTransmission();
}
//byte expanderRead() {
// byte _data = 0;
// Wire.requestFrom(EXPANDER, 1);
// if (Wire.available()) {
// _data = Wire.read();
// Serial.println(_data, BIN);
// }
// return _data;
//}
and scanner code
Code:
// --------------------------------------
// i2c_scanner
//
// Version 1
// This program (or code that looks like it)
// can be found in many places.
// For example on the Arduino.cc forum.
// The original author is not known.
// Version 2, Juni 2012, Using Arduino 1.0.1
// Adapted to be as simple as possible by Arduino.cc user Krodal
// Version 3, Feb 26 2013
// V3 by louarnold
// Version 4, March 3, 2013, Using Arduino 1.0.3
// by Arduino.cc user Krodal.
// Changes by louarnold removed.
// Scanning addresses changed from 0...127 to 1...119,
// according to the i2c scanner by Nick Gammon
// http://www.gammon.com.au/forum/?id=10896
// Version 5, March 28, 2013
// As version 4, but address scans now to 127.
// A sensor seems to use address 120.
//
//
// This sketch tests the standard 7-bit addresses
// Devices with higher bit address might not be seen properly.
//
#include <Wire.h>
void setup()
{
Wire.begin();
Serial.begin(9600);
Serial.println("\nI2C Scanner");
}
void loop()
{
byte error, address;
int nDevices;
Serial.println("Scanning...");
nDevices = 0;
for(address = 1; address < 127; address++ )
{
// The i2c_scanner uses the return value of
// the Write.endTransmisstion to see if
// a device did acknowledge to the address.
Wire.beginTransmission(address);
error = Wire.endTransmission();
if (error == 0)
{
Serial.print("I2C device found at address 0x");
if (address<16)
Serial.print("0");
Serial.print(address,HEX);
Serial.println(" !");
nDevices++;
}
else if (error==4)
{
Serial.print("Unknow error at address 0x");
if (address<16)
Serial.print("0");
Serial.println(address,HEX);
}
}
if (nDevices == 0)
Serial.println("No I2C devices found\n");
else
Serial.println("done\n");
delay(5000); // wait 5 seconds for next scan
}