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UPDATE 2.0 VERSION

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Renzo Mischianti 2020-03-06 22:22:26 +01:00
commit f8d02a8b34
5 changed files with 260 additions and 184 deletions
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191
PCF8574.cpp
View File

@ -169,14 +169,16 @@ void PCF8574::begin(){
if (writeMode>0 || readMode>0){ if (writeMode>0 || readMode>0){
DEBUG_PRINTLN("Set write mode"); DEBUG_PRINTLN("Set write mode");
_wire->beginTransmission(_address); _wire->beginTransmission(_address);
DEBUG_PRINT(" ");
DEBUG_PRINT("usedPin pin ");
byte usedPin = writeMode | readMode; DEBUG_PRINT("resetInitial pin ");
DEBUG_PRINTLN( ~usedPin, BIN); resetInitial = writeModeUp | readModePullUp;
DEBUG_PRINTLN( resetInitial, BIN);
_wire->write(~usedPin); _wire->write(resetInitial);
byteBuffered = resetInitial;
writeByteBuffered = writeModeUp;
DEBUG_PRINTLN("Start end trasmission if stop here check pullup resistor."); DEBUG_PRINTLN("Start end trasmission if stop here check pullup resistor.");
_wire->endTransmission(); _wire->endTransmission();
@ -184,9 +186,12 @@ void PCF8574::begin(){
// If using interrupt set interrupt value to pin // If using interrupt set interrupt value to pin
if (_usingInterrupt){ if (_usingInterrupt){
// DEBUG_PRINTLN("Using interrupt pin (not all pin is interrupted)");
// ::pinMode(_interruptPin, INPUT_PULLUP);
// attachInterrupt(digitalPinToInterrupt(_interruptPin), (*_interruptFunction), FALLING );
DEBUG_PRINTLN("Using interrupt pin (not all pin is interrupted)"); DEBUG_PRINTLN("Using interrupt pin (not all pin is interrupted)");
::pinMode(_interruptPin, INPUT_PULLUP); ::pinMode(_interruptPin, INPUT_PULLUP);
attachInterrupt(digitalPinToInterrupt(_interruptPin), (*_interruptFunction), FALLING ); attachInterrupt(digitalPinToInterrupt(_interruptPin), (*_interruptFunction), CHANGE );
} }
// inizialize last read // inizialize last read
@ -196,9 +201,10 @@ void PCF8574::begin(){
/** /**
* Set if fin is OUTPUT or INPUT * Set if fin is OUTPUT or INPUT
* @param pin: pin to set * @param pin: pin to set
* @param mode: mode, supported only INPUT or OUTPUT (to semplify) * @param mode: mode, supported only INPUT or OUTPUT (to simplify)
* @param output_start: output_start, for OUTPUT we can set initial value
*/ */
void PCF8574::pinMode(uint8_t pin, uint8_t mode){ void PCF8574::pinMode(uint8_t pin, uint8_t mode, uint8_t output_start){
DEBUG_PRINT("Set pin "); DEBUG_PRINT("Set pin ");
DEBUG_PRINT(pin); DEBUG_PRINT(pin);
DEBUG_PRINT(" as "); DEBUG_PRINT(" as ");
@ -206,26 +212,60 @@ void PCF8574::pinMode(uint8_t pin, uint8_t mode){
if (mode == OUTPUT){ if (mode == OUTPUT){
writeMode = writeMode | bit(pin); writeMode = writeMode | bit(pin);
if (output_start==HIGH) {
writeModeUp = writeModeUp | bit(pin);
}
readMode = readMode & ~bit(pin); readMode = readMode & ~bit(pin);
DEBUG_PRINT("writeMode: "); readModePullDown = readModePullDown & ~bit(pin);
readModePullUp = readModePullUp & ~bit(pin);
DEBUG_PRINT("W: ");
DEBUG_PRINT(writeMode, BIN); DEBUG_PRINT(writeMode, BIN);
DEBUG_PRINT("readMode: "); DEBUG_PRINT(" R ALL: ");
DEBUG_PRINTLN(readMode, BIN); DEBUG_PRINT(readMode, BIN);
DEBUG_PRINT(" R Down: ");
DEBUG_PRINT(readModePullDown, BIN);
DEBUG_PRINT("R Up: ");
DEBUG_PRINTLN(readModePullUp, BIN);
}else if (mode == INPUT){ }else if (mode == INPUT){
writeMode = writeMode & ~bit(pin); writeMode = writeMode & ~bit(pin);
readMode = readMode | bit(pin);
DEBUG_PRINT("writeMode: "); readMode = readMode | bit(pin);
readModePullDown = readModePullDown | bit(pin);
readModePullUp = readModePullUp & ~bit(pin);
DEBUG_PRINT("W: ");
DEBUG_PRINT(writeMode, BIN); DEBUG_PRINT(writeMode, BIN);
DEBUG_PRINT("readMode: "); DEBUG_PRINT(" R ALL: ");
DEBUG_PRINTLN(readMode, BIN); DEBUG_PRINT(readMode, BIN);
DEBUG_PRINT(" R Down: ");
DEBUG_PRINT(readModePullDown, BIN);
DEBUG_PRINT("R Up: ");
DEBUG_PRINTLN(readModePullUp, BIN);
}else if (mode == INPUT_PULLUP){
writeMode = writeMode & ~bit(pin);
readMode = readMode | bit(pin);
readModePullDown = readModePullDown & ~bit(pin);
readModePullUp = readModePullUp | bit(pin);
DEBUG_PRINT("W: ");
DEBUG_PRINT(writeMode, BIN);
DEBUG_PRINT(" R ALL: ");
DEBUG_PRINT(readMode, BIN);
DEBUG_PRINT(" R Down: ");
DEBUG_PRINT(readModePullDown, BIN);
DEBUG_PRINT("R Up: ");
DEBUG_PRINTLN(readModePullUp, BIN);
} }
else{ else{
DEBUG_PRINTLN("Mode non supported by PCF8574") DEBUG_PRINTLN("Mode non supported by PCF8574")
} }
DEBUG_PRINT("Write mode: ");
DEBUG_PRINTLN(writeMode, BIN);
}; };
/** /**
@ -239,8 +279,9 @@ void PCF8574::readBuffer(bool force){
if(_wire->available()) // If bytes are available to be recieved if(_wire->available()) // If bytes are available to be recieved
{ {
byte iInput = _wire->read();// Read a byte byte iInput = _wire->read();// Read a byte
if ((iInput & readMode)>0){ if ((iInput & readModePullDown)>0 and (~iInput & readModePullUp)>0){
byteBuffered = byteBuffered | (byte)iInput; // if ((iInput & readMode)>0){
byteBuffered = (byteBuffered & ~readMode) | (byte)iInput;
} }
} }
} }
@ -261,13 +302,9 @@ void PCF8574::readBuffer(bool force){
DEBUG_PRINTLN("Data ready"); DEBUG_PRINTLN("Data ready");
byte iInput = _wire->read();// Read a byte byte iInput = _wire->read();// Read a byte
if ((iInput & readMode)>0){ if ((readModePullDown & iInput)>0 or (readModePullUp & ~iInput)>0){
DEBUG_PRINT("Input "); DEBUG_PRINT(" -------- CHANGE --------- ");
DEBUG_PRINTLN((byte)iInput, BIN); byteBuffered = (byteBuffered & ~readMode) | (byte)iInput;
byteBuffered = byteBuffered | (byte)iInput;
DEBUG_PRINT("byteBuffered ");
DEBUG_PRINTLN(byteBuffered, BIN);
} }
} }
@ -283,11 +320,11 @@ void PCF8574::readBuffer(bool force){
if ((bit(6) & readMode)>0) digitalInput.p6 = ((byteBuffered & bit(6))>0)?HIGH:LOW; if ((bit(6) & readMode)>0) digitalInput.p6 = ((byteBuffered & bit(6))>0)?HIGH:LOW;
if ((bit(7) & readMode)>0) digitalInput.p7 = ((byteBuffered & bit(7))>0)?HIGH:LOW; if ((bit(7) & readMode)>0) digitalInput.p7 = ((byteBuffered & bit(7))>0)?HIGH:LOW;
if ((readMode & byteBuffered)>0){ //if ((byteBuffered & readModePullDown)>0 and (~byteBuffered & readModePullUp)>0){
byteBuffered = ~readMode & byteBuffered; byteBuffered = (resetInitial & readMode) | (byteBuffered & ~readMode); //~readMode & byteBuffered;
DEBUG_PRINT("Buffer hight value readed set readed "); DEBUG_PRINT("Buffer hight value readed set readed ");
DEBUG_PRINTLN(byteBuffered, BIN); DEBUG_PRINTLN(byteBuffered, BIN);
} //}
DEBUG_PRINT("Return value "); DEBUG_PRINT("Return value ");
return digitalInput; return digitalInput;
}; };
@ -306,13 +343,10 @@ void PCF8574::readBuffer(bool force){
DEBUG_PRINTLN("Data ready"); DEBUG_PRINTLN("Data ready");
byte iInput = _wire->read();// Read a byte byte iInput = _wire->read();// Read a byte
if ((iInput & readMode)>0){ if ((readModePullDown & iInput)>0 or (readModePullUp & ~iInput)>0){
DEBUG_PRINT("Input "); DEBUG_PRINT(" -------- CHANGE --------- ");
DEBUG_PRINTLN((byte)iInput, BIN); byteBuffered = (byteBuffered & ~readMode) | (byte)iInput;
byteBuffered = byteBuffered | (byte)iInput;
DEBUG_PRINT("byteBuffered ");
DEBUG_PRINTLN(byteBuffered, BIN);
} }
} }
@ -321,11 +355,11 @@ void PCF8574::readBuffer(bool force){
byte byteRead = byteBuffered; byte byteRead = byteBuffered;
if ((readMode & byteBuffered)>0){ //if ((byteBuffered & readModePullDown)>0 and (~byteBuffered & readModePullUp)>0){
byteBuffered = ~readMode & byteBuffered; byteBuffered = (resetInitial & readMode) | (byteBuffered & ~readMode); //~readMode & byteBuffered;
DEBUG_PRINT("Buffer hight value readed set readed "); DEBUG_PRINT("Buffer hight value readed set readed ");
DEBUG_PRINTLN(byteBuffered, BIN); DEBUG_PRINTLN(byteBuffered, BIN);
} //}
DEBUG_PRINT("Return value "); DEBUG_PRINT("Return value ");
return byteRead; return byteRead;
}; };
@ -338,45 +372,62 @@ void PCF8574::readBuffer(bool force){
* @return * @return
*/ */
uint8_t PCF8574::digitalRead(uint8_t pin){ uint8_t PCF8574::digitalRead(uint8_t pin){
uint8_t value = LOW; uint8_t value = (bit(pin) & readModePullUp)?HIGH:LOW;
DEBUG_PRINT("Read pin "); DEBUG_PRINT("Read pin ");
DEBUG_PRINTLN(pin); DEBUG_PRINT (pin);
// Check if pin already HIGH than read and prevent reread of i2c // Check if pin already HIGH than read and prevent reread of i2c
if ((bit(pin) & byteBuffered)>0){ // DEBUG_PRINTLN("----------------------------------")
DEBUG_PRINTLN("Pin already up"); // DEBUG_PRINT("readModePullUp ");
value = HIGH; // DEBUG_PRINTLN(readModePullUp, BIN);
// DEBUG_PRINT("readModePullDown ");
// DEBUG_PRINTLN(readModePullDown, BIN);
// DEBUG_PRINT("byteBuffered ");
// DEBUG_PRINTLN(byteBuffered, BIN);
if (((bit(pin) & (readModePullDown & byteBuffered))>0) or (bit(pin) & (readModePullUp & ~byteBuffered))>0 ){
DEBUG_PRINTLN(" ...Pin already set");
if ((bit(pin) & byteBuffered)>0){
value = HIGH;
}else{
value = LOW;
}
}else if ((/*(bit(pin) & byteBuffered)<=0 && */millis() > PCF8574::lastReadMillis+READ_ELAPSED_TIME) /*|| _usingInterrupt*/){ }else if ((/*(bit(pin) & byteBuffered)<=0 && */millis() > PCF8574::lastReadMillis+READ_ELAPSED_TIME) /*|| _usingInterrupt*/){
DEBUG_PRINTLN("Read from buffer"); DEBUG_PRINT(" ...Read from buffer... ");
_wire->requestFrom(_address,(uint8_t)1);// Begin transmission to PCF8574 with the buttons _wire->requestFrom(_address,(uint8_t)1);// Begin transmission to PCF8574 with the buttons
lastReadMillis = millis(); lastReadMillis = millis();
if(_wire->available()) // If bytes are available to be recieved if(_wire->available()) // If bytes are available to be recieved
{ {
DEBUG_PRINTLN("Data ready"); DEBUG_PRINTLN(" Data ready");
byte iInput = _wire->read();// Read a byte byte iInput = _wire->read();// Read a byte
DEBUG_PRINT("Input ");
DEBUG_PRINT((byte)iInput, BIN);
if ((iInput & readMode)>0){ if ((readModePullDown & iInput)>0 or (readModePullUp & ~iInput)>0){
DEBUG_PRINT("Input "); DEBUG_PRINT(" -------- CHANGE --------- ");
DEBUG_PRINTLN((byte)iInput, BIN); byteBuffered = (byteBuffered & ~readMode) | (byte)iInput;
byteBuffered = byteBuffered | (byte)iInput;
DEBUG_PRINT("byteBuffered ");
DEBUG_PRINTLN(byteBuffered, BIN);
if ((bit(pin) & byteBuffered)>0){ if ((bit(pin) & byteBuffered)>0){
value = HIGH; value = HIGH;
}else{
value = LOW;
} }
// value = (bit(pin) & byteBuffered);
} }
} }
} }
DEBUG_PRINT("Buffer value "); DEBUG_PRINT(" ..Buffer value ");
DEBUG_PRINTLN(byteBuffered, BIN); DEBUG_PRINT(byteBuffered, BIN);
// If HIGH set to low to read buffer only one time // If HIGH set to low to read buffer only one time
if (value==HIGH){ if ((bit(pin) & readModePullDown) and value==HIGH){
byteBuffered = ~bit(pin) & byteBuffered; byteBuffered = bit(pin) ^ byteBuffered;
DEBUG_PRINT("Buffer hight value readed set readed "); DEBUG_PRINT(" ...Buffer hight value readed set readed ");
DEBUG_PRINTLN(byteBuffered, BIN); DEBUG_PRINT (byteBuffered, BIN);
}else if ((bit(pin) & readModePullUp) and value==LOW){
byteBuffered = bit(pin) ^ byteBuffered;
DEBUG_PRINT(" ...Buffer low value readed set readed ");
DEBUG_PRINT(byteBuffered, BIN);
} }
DEBUG_PRINT("Return value "); DEBUG_PRINT(" ...Return value ");
DEBUG_PRINTLN(value); DEBUG_PRINTLN(value);
return value; return value;
}; };
@ -389,10 +440,17 @@ uint8_t PCF8574::digitalRead(uint8_t pin){
void PCF8574::digitalWrite(uint8_t pin, uint8_t value){ void PCF8574::digitalWrite(uint8_t pin, uint8_t value){
DEBUG_PRINTLN("Begin trasmission"); DEBUG_PRINTLN("Begin trasmission");
_wire->beginTransmission(_address); //Begin the transmission to PCF8574 _wire->beginTransmission(_address); //Begin the transmission to PCF8574
DEBUG_PRINT("Value ");
DEBUG_PRINT(value);
DEBUG_PRINT(" Write data pre ");
DEBUG_PRINT(writeByteBuffered, BIN);
if (value==HIGH){ if (value==HIGH){
writeByteBuffered = writeByteBuffered | bit(pin); writeByteBuffered = writeByteBuffered | bit(pin);
byteBuffered = writeByteBuffered | bit(pin);
}else{ }else{
writeByteBuffered = writeByteBuffered & ~bit(pin); writeByteBuffered = writeByteBuffered & ~bit(pin);
byteBuffered = writeByteBuffered & ~bit(pin);
} }
DEBUG_PRINT("Write data "); DEBUG_PRINT("Write data ");
DEBUG_PRINT(writeByteBuffered, BIN); DEBUG_PRINT(writeByteBuffered, BIN);
@ -401,10 +459,15 @@ void PCF8574::digitalWrite(uint8_t pin, uint8_t value){
DEBUG_PRINT(" bin value "); DEBUG_PRINT(" bin value ");
DEBUG_PRINT(bit(pin), BIN); DEBUG_PRINT(bit(pin), BIN);
DEBUG_PRINT(" value "); DEBUG_PRINT(" value ");
DEBUG_PRINTLN(value); DEBUG_PRINT(value);
writeByteBuffered = writeByteBuffered & writeMode; // writeByteBuffered = writeByteBuffered & (~writeMode & byteBuffered);
_wire->write(writeByteBuffered); byteBuffered = (writeByteBuffered & writeMode) | (resetInitial & readMode);
DEBUG_PRINT(" byteBuffered ");
DEBUG_PRINTLN(byteBuffered, BIN);
_wire->write(byteBuffered);
// byteBuffered = (writeByteBuffered & writeMode) & (byteBuffered & readMode);
DEBUG_PRINTLN("Start end trasmission if stop here check pullup resistor."); DEBUG_PRINTLN("Start end trasmission if stop here check pullup resistor.");
_wire->endTransmission(); _wire->endTransmission();

21
PCF8574.h
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@ -45,6 +45,9 @@
// Uncomment for low memory usage this prevent use of complex DigitalInput structure and free 7byte of memory // Uncomment for low memory usage this prevent use of complex DigitalInput structure and free 7byte of memory
// #define PCF8574_LOW_MEMORY // #define PCF8574_LOW_MEMORY
// Uncomment for low memory usage this prevent use of complex DigitalInput structure and free 7byte of memory
// #define PCF8574_LOW_LATENCY
// Define where debug output will be printed. // Define where debug output will be printed.
#define DEBUG_PRINTER Serial #define DEBUG_PRINTER Serial
@ -57,7 +60,11 @@
#define DEBUG_PRINTLN(...) {} #define DEBUG_PRINTLN(...) {}
#endif #endif
#define READ_ELAPSED_TIME 10 #ifdef PCF8574_LOW_LATENCY
#define READ_ELAPSED_TIME 1
#else
#define READ_ELAPSED_TIME 10
#endif
//#define P0 B00000001 //#define P0 B00000001
//#define P1 B00000010 //#define P1 B00000010
@ -101,7 +108,7 @@ public:
#endif #endif
void begin(); void begin();
void pinMode(uint8_t pin, uint8_t mode); void pinMode(uint8_t pin, uint8_t mode, uint8_t output_start = HIGH);
void readBuffer(bool force = true); void readBuffer(bool force = true);
uint8_t digitalRead(uint8_t pin); uint8_t digitalRead(uint8_t pin);
@ -145,9 +152,13 @@ private:
uint8_t _interruptPin = 2; uint8_t _interruptPin = 2;
void (*_interruptFunction)(){}; void (*_interruptFunction)(){};
byte writeMode = B00000000; byte writeMode = B00000000;
byte readMode = B00000000; byte writeModeUp = B00000000;
byte byteBuffered = B00000000; byte readMode = B00000000;
byte readModePullUp = B00000000;
byte readModePullDown = B00000000;
byte byteBuffered = B00000000;
byte resetInitial = B00000000;
unsigned long lastReadMillis = 0; unsigned long lastReadMillis = 0;
byte writeByteBuffered = B00000000; byte writeByteBuffered = B00000000;

230
README.md
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@ -1,114 +1,116 @@
### Additional information and document update here on my site: [pcf8574 Article](https://www.mischianti.org/2019/01/02/pcf8574-i2c-digital-i-o-expander-fast-easy-usage/). ### Additional information and document update here on my site: [pcf8574 Article](https://www.mischianti.org/2019/01/02/pcf8574-i2c-digital-i-o-expander-fast-easy-usage/).
### If you need more pins [here](https://www.mischianti.org/2019/07/22/pcf8575-i2c-16-bit-digital-i-o-expander/) you can find pcf8575 16bit version of the IC. ### If you need more pins [here](https://www.mischianti.org/2019/07/22/pcf8575-i2c-16-bit-digital-i-o-expander/) you can find pcf8575 16bit version of the IC.
Library to use i2c analog IC with arduino and esp8266. Can read and write digital value with only 2 wire (perfect for ESP-01). ### Version 2.0
Tutorial: Library to use i2c analog IC with arduino and esp8266. Can read and write digital value with only 2 wire (perfect for ESP-01).
To download. click the DOWNLOADS button in the top right corner, rename the uncompressed folder PCF8574. Check that the PCF8574 folder contains `PCF8574\\.cpp` and `PCF8574.h`. Place the DHT library folder your `<arduinosketchfolder>/libraries/` folder. You may need to create the libraries subfolder if its your first library. Restart the IDE. Tutorial:
# Reef complete PCF8574 PCF8574AP digital input and output expander with i2c bus. To download. click the DOWNLOADS button in the top right corner, rename the uncompressed folder PCF8574. Check that the PCF8574 folder contains `PCF8574\\.cpp` and `PCF8574.h`. Place the DHT library folder your `<arduinosketchfolder>/libraries/` folder. You may need to create the libraries subfolder if its your first library. Restart the IDE.
I try to simplify the use of this IC, with a minimal set of operation.
# Reef complete PCF8574 PCF8574AP digital input and output expander with i2c bus.
PCF8574P address map 0x20-0x27 I try to simplify the use of this IC, with a minimal set of operation.
PCF8574AP address map 0x38-0x3f
PCF8574P address map 0x20-0x27
Constructor: PCF8574AP address map 0x38-0x3f
you must pas the address of i2c (to check the adress use this guide [I2cScanner](https://playground.arduino.cc/Main/I2cScanner))
```cpp Constructor:
PCF8574(uint8_t address); you must pas the address of i2c (to check the adress use this guide [I2cScanner](https://playground.arduino.cc/Main/I2cScanner))
``` ```cpp
for esp8266 if you want specify SDA e SCL pin use this: PCF8574(uint8_t address);
```
```cpp for esp8266 if you want specify SDA e SCL pin use this:
PCF8574(uint8_t address, uint8_t sda, uint8_t scl);
``` ```cpp
You must set input/output mode: PCF8574(uint8_t address, uint8_t sda, uint8_t scl);
```cpp ```
pcf8574.pinMode(P0, OUTPUT); You must set input/output mode:
pcf8574.pinMode(P1, INPUT); ```cpp
pcf8574.pinMode(P2, INPUT); pcf8574.pinMode(P0, OUTPUT);
``` pcf8574.pinMode(P1, INPUT);
pcf8574.pinMode(P2, INPUT);
then IC as you can see in the image have 8 digital input/output: ```
![PCF8574 schema](https://github.com/xreef/PCF8574_library/blob/master/resources/PCF8574-pins.gif) then IC as you can see in the image have 8 digital input/output:
So to read all analog input in one trasmission you can do (even if I use a 10millis debounce time to prevent too much read from i2c): ![PCF8574 schema](https://github.com/xreef/PCF8574_library/blob/master/resources/PCF8574-pins.gif)
```cpp
PCF8574::DigitalInput di = PCF8574.digitalReadAll(); So to read all analog input in one trasmission you can do (even if I use a 10millis debounce time to prevent too much read from i2c):
Serial.print(di.p0); ```cpp
Serial.print(" - "); PCF8574::DigitalInput di = PCF8574.digitalReadAll();
Serial.print(di.p1); Serial.print(di.p0);
Serial.print(" - "); Serial.print(" - ");
Serial.print(di.p2); Serial.print(di.p1);
Serial.print(" - "); Serial.print(" - ");
Serial.println(di.p3); Serial.print(di.p2);
``` Serial.print(" - ");
Serial.println(di.p3);
To follow a request (you can see It on [issue #5](https://github.com/xreef/PCF8574_library/issues/5)) I create a define variable to work with low memori device, if you decomment this line on .h file of the library: ```
```cpp To follow a request (you can see It on [issue #5](https://github.com/xreef/PCF8574_library/issues/5)) I create a define variable to work with low memori device, if you decomment this line on .h file of the library:
// #define PCF8574_LOW_MEMORY
``` ```cpp
// #define PCF8574_LOW_MEMORY
Enable low memory props and gain about 7byte of memory, and you must use the method to read all like so: ```
```cpp Enable low memory props and gain about 7byte of memory, and you must use the method to read all like so:
byte di = pcf8574.digitalReadAll();
Serial.print("READ VALUE FROM PCF: "); ```cpp
Serial.println(di, BIN); byte di = pcf8574.digitalReadAll();
``` Serial.print("READ VALUE FROM PCF: ");
Serial.println(di, BIN);
where di is a byte like 1110001, so you must do a bitwise operation to get the data, operation that I already do in the "normal" mode, here an example: ```
```cpp where di is a byte like 1110001, so you must do a bitwise operation to get the data, operation that I already do in the "normal" mode, here an example:
p0 = ((di & bit(0))>0)?HIGH:LOW;
p1 = ((di & bit(1))>0)?HIGH:LOW; ```cpp
p2 = ((di & bit(2))>0)?HIGH:LOW; p0 = ((di & bit(0))>0)?HIGH:LOW;
p3 = ((di & bit(3))>0)?HIGH:LOW; p1 = ((di & bit(1))>0)?HIGH:LOW;
p4 = ((di & bit(4))>0)?HIGH:LOW; p2 = ((di & bit(2))>0)?HIGH:LOW;
p5 = ((di & bit(5))>0)?HIGH:LOW; p3 = ((di & bit(3))>0)?HIGH:LOW;
p6 = ((di & bit(6))>0)?HIGH:LOW; p4 = ((di & bit(4))>0)?HIGH:LOW;
p7 = ((di & bit(7))>0)?HIGH:LOW; p5 = ((di & bit(5))>0)?HIGH:LOW;
``` p6 = ((di & bit(6))>0)?HIGH:LOW;
p7 = ((di & bit(7))>0)?HIGH:LOW;
```
if you want read a single input:
```cpp if you want read a single input:
int p1Digital = PCF8574.digitalRead(P1); // read P1
``` ```cpp
int p1Digital = PCF8574.digitalRead(P1); // read P1
If you want write a digital value you must do: ```
```cpp
PCF8574.digitalWrite(P1, HIGH); If you want write a digital value you must do:
``` ```cpp
or: PCF8574.digitalWrite(P1, HIGH);
```cpp ```
PCF8574.digitalWrite(P1, LOW); or:
``` ```cpp
PCF8574.digitalWrite(P1, LOW);
You can also use interrupt pin: ```
You must initialize the pin and the function to call when interrupt raised from PCF8574
```cpp You can also use interrupt pin:
// Function interrupt You must initialize the pin and the function to call when interrupt raised from PCF8574
void keyPressedOnPCF8574(); ```cpp
// Function interrupt
// Set i2c address void keyPressedOnPCF8574();
PCF8574 pcf8574(0x39, ARDUINO_UNO_INTERRUPT_PIN, keyPressedOnPCF8574);
``` // Set i2c address
Remember you can't use Serial or Wire on interrupt function. PCF8574 pcf8574(0x39, ARDUINO_UNO_INTERRUPT_PIN, keyPressedOnPCF8574);
```
The better way is to set only a variable to read on loop: Remember you can't use Serial or Wire on interrupt function.
```cpp
void keyPressedOnPCF8574(){ The better way is to set only a variable to read on loop:
// Interrupt called (No Serial no read no wire in this function, and DEBUG disabled on PCF library) ```cpp
keyPressed = true; void keyPressedOnPCF8574(){
} // Interrupt called (No Serial no read no wire in this function, and DEBUG disabled on PCF library)
``` keyPressed = true;
}
For the examples I use this wire schema on breadboard: ```
![Breadboard](https://github.com/xreef/PCF8574_library/blob/master/resources/testReadWriteLedButton_bb.png)
For the examples I use this wire schema on breadboard:
![Breadboard](https://github.com/xreef/PCF8574_library/blob/master/resources/testReadWriteLedButton_bb.png)

2
library.properties
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@ -1,5 +1,5 @@
name=PCF8574 library name=PCF8574 library
version=1.2.0 version=2.0.0
author=Reef author=Reef
maintainer=Renzo Mischianti <renzo.mischianti@gmail.com> maintainer=Renzo Mischianti <renzo.mischianti@gmail.com>
sentence=Arduino/ESP8266 library for PCF8574 sentence=Arduino/ESP8266 library for PCF8574

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