45 lines
1.2 KiB
C++
45 lines
1.2 KiB
C++
#include "RowScanner_SPIShiftRegisters.h"
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//constructor
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RowScanner_SPIShiftRegisters::RowScanner_SPIShiftRegisters(const uint8_t STROBE_PIN, uint8_t KEY_COUNT)
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: STROBE_PIN(STROBE_PIN), BYTE_COUNT(ceil (float(KEY_COUNT)/8)), KEY_COUNT(KEY_COUNT)
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{
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//configure controller to communicate with shift register matrix
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pinMode(STROBE_PIN, OUTPUT);
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pinMode(SHIFT_LOAD, OUTPUT);
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}
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void RowScanner_SPIShiftRegisters::begin()
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{
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//initialize shift register's shift/load pin
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digitalWrite(SHIFT_LOAD, HIGH);
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}
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/*
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Sets keyCount and returns rowState.
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*/
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read_pins_t RowScanner_SPIShiftRegisters::scan(uint8_t& keyCount)
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{
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read_pins_t rowState = 0;
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//strobe row on
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digitalWrite(STROBE_PIN, STROBE_ON);
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delayMicroseconds(3); //time to stablize voltage
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//read all the column pins
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digitalWrite(SHIFT_LOAD, LOW); //load parallel inputs to the register
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digitalWrite(SHIFT_LOAD, HIGH); //shift the data toward a serial output
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SPI.transfer(&rowState, BYTE_COUNT);
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//strobe row off
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digitalWrite(STROBE_PIN, STROBE_OFF);
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keyCount = KEY_COUNT;
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//for testing on breadboard, clear unpowered pins
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rowState &= 0b11110001000100010001000100010001; //todo
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return rowState;
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}
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