70 righe
2.0 KiB
C++
70 righe
2.0 KiB
C++
#include "Scanner_uC.h"
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/* Scanner_uC functions call Arduino's Digital Pins functions
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https://www.arduino.cc/en/Tutorial/DigitalPins
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https://www.arduino.cc/en/Reference/PinMode
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https://www.arduino.cc/en/Reference/DigitalWrite
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https://www.arduino.cc/en/Reference/DigitalRead
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https://www.arduino.cc/en/Reference/Constants > Digital Pins modes: INPUT, INPUT_PULLUP, and OUTPUT
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*/
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/* constructor
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*/
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Scanner_uC::Scanner_uC(const bool activeState, const uint8_t readPins[], const uint8_t readPinCount)
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: activeState(activeState), readPins(readPins), readPinCount(readPinCount)
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{
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uint8_t mode;
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//configure read pins
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if (activeState == LOW) //if active low
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{
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mode = INPUT_PULLUP; //use internal pull-up resistor
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}
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else //if active high
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{
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mode = INPUT; //requires external pull-down resistor
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}
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for (uint8_t i=0; i < readPinCount; i++)
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{
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pinMode(readPins[i], mode);
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}
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}
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/* init() is called once for each row from Row constructor.
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Configure row-strobe pin to output.
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*/
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void Scanner_uC::init(const uint8_t strobePin)
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{
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pinMode(strobePin, OUTPUT);
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}
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/* scan() is called on every iteration of sketch loop().
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scan() strobes the row's strobePin and retuns state of readPins.
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Bit patterns are 1 bit per key.
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*/
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read_pins_t Scanner_uC::scan(const uint8_t strobePin)
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{
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read_pins_t readState = 0; //bits, 1 means key is pressed, 0 means released
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read_pins_t readMask = 1; //bits, active bit is 1
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//strobe on
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digitalWrite(strobePin, activeState);
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delayMicroseconds(3); //time to stablize voltage
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//read all the read pins
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for (uint8_t i=0; i < readPinCount; i++)
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{
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if ( digitalRead(readPins[i]) == activeState )
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{
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readState |= readMask;
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}
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readMask <<= 1;
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}
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//strobe off
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digitalWrite(strobePin, !activeState);
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return readState;
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}
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