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- #include "Scanner_uC.h"
-
- /* constructor
- */
- Scanner_uC::Scanner_uC(const uint8_t STROBE_PIN,
- const uint8_t READ_PINS[], const uint8_t READ_PIN_COUNT)
- : STROBE_PIN(STROBE_PIN), READ_PINS(READ_PINS), READ_PIN_COUNT(READ_PIN_COUNT)
- {
- uint8_t mode;
-
- //configure row
- pinMode(STROBE_PIN, OUTPUT);
-
- if (STROBE_ON == LOW) //if active low
- {
- mode = INPUT_PULLUP; //uses internal pull-up resistor
- }
- else
- {
- mode = INPUT; //requires external pull-down resistor
- }
-
- //configure read pins
- for (uint8_t i=0; i < READ_PIN_COUNT; i++)
- {
- pinMode(READ_PINS[i], mode);
- }
- }
-
- /* scan() Strobes the row and reads the columns.
- Sets READ_PIN_COUNT and returns rowState.
-
- https://www.arduino.cc/en/Tutorial/DigitalPins
- https://www.arduino.cc/en/Reference/PinMode
- https://www.arduino.cc/en/Reference/DigitalWrite
- https://www.arduino.cc/en/Reference/DigitalRead
- https://www.arduino.cc/en/Reference/Constants > Digital Pins modes: INPUT, INPUT_PULLUP, and OUTPUT
- */
- read_pins_t Scanner_uC::scan()
- {
- read_pins_t rowState = 0; //bitwise, one col per bit, 1 means key is pressed
- read_pins_t readMask = 1; //bitwise, one col per bit, active col bit is 1
-
- //strobe row on
- digitalWrite(STROBE_PIN, STROBE_ON);
- delayMicroseconds(3); //time to stablize voltage
-
- //read all the read pins
- for (uint8_t i=0; i < READ_PIN_COUNT; i++)
- {
- if ( digitalRead(READ_PINS[i]) == STROBE_ON )
- {
- rowState |= readMask;
- }
- readMask <<= 1;
- }
-
- //strobe row off
- digitalWrite(STROBE_PIN, STROBE_OFF);
-
- // readPinCount = READ_PIN_COUNT;
- return rowState;
- }
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