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- #include "Scanner_ShiftRegs74HC165.h"
-
- //constructor
- Scanner_ShiftRegs74HC165::Scanner_ShiftRegs74HC165(const uint8_t STROBE_PIN, uint8_t READ_PIN_COUNT)
- : STROBE_PIN(STROBE_PIN), BYTE_COUNT(ceil (float(READ_PIN_COUNT)/8))
- {
- //configure controller to communicate with shift register matrix
- pinMode(STROBE_PIN, OUTPUT);
- pinMode(SHIFT_LOAD, OUTPUT);
- }
-
- void Scanner_ShiftRegs74HC165::begin()
- {
- //initialize shift register's shift/load pin
- digitalWrite(SHIFT_LOAD, HIGH);
- }
-
- /*
- returns readState.
- */
- read_pins_t Scanner_ShiftRegs74HC165::scan()
- {
- read_pins_t readState = 0;
-
- //strobe row on
- digitalWrite(STROBE_PIN, STROBE_ON);
- delayMicroseconds(3); //time to stablize voltage
-
- //read all the column pins
- digitalWrite(SHIFT_LOAD, LOW); //load parallel inputs to the register
- digitalWrite(SHIFT_LOAD, HIGH); //shift the data toward a serial output
- SPI.transfer(&readState, BYTE_COUNT);
-
- //strobe row off
- digitalWrite(STROBE_PIN, STROBE_OFF);
-
- //for testing on breadboard, clear unpowered pins
- readState &= 0b11110001000100010001000100010001; //todo
-
- return readState;
- }
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