46 rader
1.3 KiB
C++
46 rader
1.3 KiB
C++
#include "Scanner_ShiftRegsRead.h"
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/* constructor
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Parameter activeState is not used.
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*/
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Scanner_ShiftRegsRead::Scanner_ShiftRegsRead(const bool activeState,
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const uint8_t slaveSelect, const uint8_t byte_count)
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: slaveSelect(slaveSelect), byte_count(byte_count)
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{
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pinMode(slaveSelect, OUTPUT);
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}
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/* init() is called once for each row from Row constructor.
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*/
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void Scanner_ShiftRegsRead::init(const uint8_t strobePin)
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{
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//empty function
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}
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/* begin() should be called once from sketch setup().
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Initializes shift register's shift/load pin.
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*/
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void Scanner_ShiftRegsRead::begin()
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{
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SPI.begin();
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digitalWrite(slaveSelect, HIGH);
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}
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/* scan() returns state of the shift register's input pins.
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Parameter strobePin is not used.
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No strobe pin is needed, the shift register is wired so the strobe is effectivley always "on".
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Bit patterns are 1 bit per key.
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*/
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read_pins_t Scanner_ShiftRegsRead::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 all the column pins
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digitalWrite(slaveSelect, HIGH); //shift the data toward a serial output
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SPI.transfer(&readState, byte_count);
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digitalWrite(slaveSelect, LOW); //load parallel inputs to the register
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return readState;
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}
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