Skip to content

Commit

Permalink
document code parts only in header file
Browse files Browse the repository at this point in the history
  • Loading branch information
@hasenradball
hasenradball committed Dec 5, 2024
1 parent f5557bc commit 08a3a2b
Show file tree
Hide file tree
Showing 2 changed files with 230 additions and 223 deletions.
134 changes: 8 additions & 126 deletions PCF8574.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -11,60 +11,29 @@

#include "PCF8574.h"

/**
* @brief Construct a new PCF8574::PCF8574 object
*
* @param deviceAddress optional address of I2C device; default = 0x20;
* @param wire optional address of Wire instance; default = \&Wire;
*/
PCF8574::PCF8574(const uint8_t deviceAddress, TwoWire *wire)
: _address {deviceAddress}, _wire {wire}
{}

/**
* @brief init PCF8574 instance
*
* @param value optional init value to write; default = 0xFF;
* @return true
* @return false
*/
bool PCF8574::begin(uint8_t value)
{
if (! isConnected()) return false;
PCF8574::write8(value);
return true;
}

/**
* @brief check if device is connected
*
* @return true
* @return false
*/
bool PCF8574::isConnected()
{
_wire->beginTransmission(_address);
return ( _wire->endTransmission() == 0);
}

/**
* @brief set address of PCF8574 device
*
* @param deviceAddress I2C address; possible values 0x20...0x27
* @return true
* @return false
*/
bool PCF8574::setAddress(const uint8_t deviceAddress)
{
_address = deviceAddress;
return isConnected();
}

/**
* @brief read all 8 bit at once from PCF8574
*
* @return uint8_t value read from device
*/
uint8_t PCF8574::read8()
{
if (_wire->requestFrom(_address, (uint8_t)1) != 1)
Expand All @@ -76,25 +45,6 @@ uint8_t PCF8574::read8()
return _dataIn;
}

/**
* @brief write all 8 bit at once to PCF8574 device
*
* @param value to write
*/
void PCF8574::write8(const uint8_t value)
{
_dataOut = value;
_wire->beginTransmission(_address);
_wire->write(_dataOut);
_error = _wire->endTransmission();
}

/**
* @brief read one bit from PCF8574 device
*
* @param pin pin to read (0...7)
* @return uint8_t value
*/
uint8_t PCF8574::read(const uint8_t pin)
{
if (pin > 7)
Expand All @@ -106,12 +56,14 @@ uint8_t PCF8574::read(const uint8_t pin)
return (_dataIn & (1 << pin)) > 0;
}

/**
* @brief writes a single pin; pin = 0..7.
*
* @param pin pin number for write (0...7)
* @param value value to write, HIGH(1) or LOW (0)
*/
void PCF8574::write8(const uint8_t value)
{
_dataOut = value;
_wire->beginTransmission(_address);
_wire->write(_dataOut);
_error = _wire->endTransmission();
}

void PCF8574::write(const uint8_t pin, const uint8_t value)
{
if (pin > 7)
Expand All @@ -130,11 +82,6 @@ void PCF8574::write(const uint8_t pin, const uint8_t value)
write8(_dataOut);
}

/**
* @brief toggle one bit on PCF8574 device
*
* @param pin pin number for write (0...7)
*/
void PCF8574::toggle(const uint8_t pin)
{
if (pin > 7)
Expand All @@ -145,23 +92,12 @@ void PCF8574::toggle(const uint8_t pin)
toggleMask(1 << pin);
}

/**
* @brief toggles a selection of pins, if you want to invert all pins use 0xFF (default value).
*
* @param mask
*/
void PCF8574::toggleMask(const uint8_t mask)
{
_dataOut ^= mask;
PCF8574::write8(_dataOut);
}

/**
* @brief shifts output channels n pins (default 1) pins right (e.g. LEDs ).
* Fills the higher lines with zero's.
*
* @param n number of shifts
*/
void PCF8574::shiftRight(const uint8_t n)
{
if ((n == 0) || (_dataOut == 0)) return;
Expand All @@ -170,12 +106,6 @@ void PCF8574::shiftRight(const uint8_t n)
PCF8574::write8(_dataOut);
}

/**
* @brief shifts output channels n pins (default 1) pins left (e.g. LEDs ).
* Fills the lower lines with zero's
*
* @param n number of shifts
*/
void PCF8574::shiftLeft(const uint8_t n)
{
if ((n == 0) || (_dataOut == 0)) return;
Expand All @@ -184,24 +114,13 @@ void PCF8574::shiftLeft(const uint8_t n)
PCF8574::write8(_dataOut);
}

/**
* @brief returns the last error from the lib (see .h file).
*
* @return int error value to return
*/
int PCF8574::lastError()
{
int e = _error;
_error = PCF8574_OK; // reset error after read, is this wise?
return e;
}

/**
* @brief rotates output channels to right,
* moving lowest line to highest line.
*
* @param n number of moves
*/
void PCF8574::rotateRight(const uint8_t n)
{
uint8_t r = n & 7;
Expand All @@ -210,22 +129,11 @@ void PCF8574::rotateRight(const uint8_t n)
PCF8574::write8(_dataOut);
}

/**
* @brief rotates output channels to left,
* moving highest line to lowest line.
*
* @param n number of moves
*/
void PCF8574::rotateLeft(const uint8_t n)
{
rotateRight(8 - (n & 7));
}

/**
* @brief reverse the "bit pattern" of the lines,
* swapping pin 7 with 0, 6 with 1, 5 with 2 etc.
*
*/
void PCF8574::reverse() // quite fast: 4 and, 14 shifts, 3 or, 3 assignment.
{
uint8_t x = _dataOut;
Expand All @@ -235,12 +143,6 @@ void PCF8574::reverse() // quite fast: 4 and, 14 shifts, 3 or, 3 assignment.
PCF8574::write8(x);
}

/**
* @brief read Button mask.
*
* @param mask use the mask set by setButtonMask to select specific input pins.
* @return * uint8_t
*/
uint8_t PCF8574::readButton8(const uint8_t mask)
{
uint8_t temp = _dataOut;
Expand All @@ -250,12 +152,6 @@ uint8_t PCF8574::readButton8(const uint8_t mask)
return _dataIn;
}

/**
* @brief read button read a single input pin.
*
* @param pin pin number to be read
* @return uint8_t value read from pin
*/
uint8_t PCF8574::readButton(const uint8_t pin)
{
if (pin > 7)
Expand All @@ -271,32 +167,18 @@ uint8_t PCF8574::readButton(const uint8_t pin)
return value;
}

/**
* @brief select sets the specified pin pin to High,
* all others set to Low. If pin > 7 all pins are set to LOW.
*
* @param pin pin which should be set to 1
*/
void PCF8574::select(const uint8_t pin)
{
uint8_t n = 0x00;
if (pin < 8) n = 1 << pin;
write8(n);
};

/**
* @brief select sets the pins from 0...pin to High,
* all others set to Low. If pin > 7 all pins are set to LOW.
*
* @param pin pin up to which should be set to 1
*/
void PCF8574::selectN(const uint8_t pin)
{
uint8_t n = 0xFF;
if (pin < 8) n = (2 << pin) - 1;
write8(n);
};


// -- END OF FILE --

Loading

0 comments on commit 08a3a2b

Please sign in to comment.