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- #include "RowScanner_PinsArray.h"
-
- /* constructor
- */
- RowScanner_PinsArray::RowScanner_PinsArray(const uint8_t strobePin,
- const uint8_t readPins[], const uint8_t READ_PIN_COUNT)
- : strobePin(strobePin), readPins(readPins), READ_PIN_COUNT(READ_PIN_COUNT)
- {
- uint8_t mode;
-
- //configure row
- pinMode(strobePin, OUTPUT);
-
- if (activeHigh)
- {
- mode = INPUT; //requires external pull-down resistor
- }
- else
- {
- mode = INPUT_PULLUP; //uses internal pull-up resistor
- }
-
- //configure cols
- for (uint8_t i=0; i < READ_PIN_COUNT; i++)
- {
- pinMode(readPins[i], mode);
- }
- }
-
- /* scan() Strobes the row and reads the columns.
- Sets rowEnd and returns rowState.
- rowEnd is a bitwise row mask, one col per bit, where active col bit is 1.
- At end of function, 1 bit marks place immediatly after last key of row.
- rowEnd is a larger type than portMask so that it can not overflow.
-
- 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 RowScanner_PinsArray::scan(read_pins_mask_t& rowEnd)
- {
- read_pins_t rowState = 0; //bitwise
- rowEnd = 1;
-
- //strobe row on
- if (activeHigh)
- {
- digitalWrite(strobePin, HIGH);
- }
- else //activeLow
- {
- digitalWrite(strobePin, LOW);
- }
- delayMicroseconds(3); //time to stablize voltage
-
- //read all the column pins
- for (uint8_t i=0; i < READ_PIN_COUNT; i++)
- {
- if ( digitalRead(readPins[i]) == activeHigh )
- {
- rowState |= rowEnd;
- }
- rowEnd <<= 1;
- }
-
- //strobe row off
- if (activeHigh)
- {
- digitalWrite(strobePin, LOW);
- }
- else //activeLow
- {
- digitalWrite(strobePin, HIGH);
- }
-
- return rowState;
- }
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