63 lines
2.1 KiB
C++
63 lines
2.1 KiB
C++
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#include "PortPCA9655E.h"
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/* begin() is called from Scanner_IOE::begin(). Initiates I2C bus.
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PCA9655E supports I2C SCL Clock Frequencies: 100 kHz, 400 kHz, 1000 kHz (Datasheet page 1 & 6)
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The electrical limitation to bus speed is bus capacitance and the length of the wires involved.
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Longer wires require lower clock speeds.
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http://playground.arduino.cc/Main/WireLibraryDetailedReference > Wire.setclock()
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*/
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void PortPCA9655E::beginProtocol()
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{
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Wire.begin(); //initiate I2C bus to 100 kHz
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//Wire.setClock(400000L); //set I2C bus to 400 kHz (have not tested 400 kHz)
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}
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/* begin() is called from Scanner_IOE::begin().
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Configures read pins to input.
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strobeOn is not used because PCA9655E has no pull-up resistors.
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*/
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void PortPCA9655E::begin(const uint8_t strobeOn)
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{
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Wire.beginTransmission(deviceAddr);
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Wire.write(portNum + 6); //configuration byte command
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Wire.write(readPins); //0=output (for strobe and LED), 1=input (for read)
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Wire.endTransmission();
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}
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/* write() sets pin output to logicLevel.
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pin is bit pattern, where pin being strobed is 1.
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logicLevel is HIGH or LOW.
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write() does not overwrite the other pins.
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*/
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void PortPCA9655E::write(const uint8_t pin, const bool logicLevel)
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{
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if (logicLevel == LOW)
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{
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outputVal &= ~pin; //set pin output to low
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}
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else
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{
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outputVal |= pin; //set pin output to high
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}
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Wire.beginTransmission(deviceAddr);
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Wire.write(portNum + 2); //output Byte command
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Wire.write(outputVal);
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Wire.endTransmission();
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}
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/* read() returns portState.
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Only portState bits of readPins are valid.
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*/
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uint8_t PortPCA9655E::read()
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{
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Wire.beginTransmission(deviceAddr);
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Wire.write(portNum); //input byte command
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Wire.endTransmission(false); //PCA9655E needs false to send a restart
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Wire.requestFrom(deviceAddr, 1u); //request one byte from input port
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return Wire.read();
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}
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