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- #ifndef ROWSCANNER_SHIFTREGS74HC165_H
- #define ROWSCANNER_SHIFTREGS74HC165_H
-
- #include <Arduino.h>
- #include <inttypes.h>
- #include <config_keybrd.h>
- #include <SPI.h>
- #include <PortWrite.h>
- #include <PortRead.h>
-
- /* Scanner_ShiftRegs74HC165 reads shift registers.
- shift registers 74HC165 are Parallel-In-Serial-Out (PISO)
- Upto 4 shift registers can be in a daisy chained for a total of 32 read pins.
-
- For active low:
- Shift register parallel input pins have 10k pull-down resistors powered
- Orient diodes with cathode (banded end) towards the write pins (row)
- Controller's MISO pin is connected to shift register's complementary serial output (/QH) pin
- Use these two lines in the sketch:
- const bool Scanner_ShiftRegs74HC165::STROBE_ON = LOW;
- const bool Scanner_ShiftRegs74HC165::STROBE_OFF = HIGH;
-
- For active high:
- Shift register parallel input pins have 10k pull-down resistors grounded
- Orient diodes with cathode (banded end) towards the read pins.
- Controller's MISO pin is connected to shift register's serial output (QH) pin
- Use these two lines in the sketch:
- const bool Scanner_ShiftRegs74HC165::STROBE_ON = HIGH;
- const bool Scanner_ShiftRegs74HC165::STROBE_OFF = LOW;
-
- In addition, each row needs to be connected to a strobe pin from the controller.
- */
- class Scanner_ShiftRegs74HC165
- {
- private:
- static const uint8_t SHIFT_LOAD; //controller's pin number that is
- // connected to shift register's SHIFT_LOAD pin
- static const bool STROBE_ON; //logic level of strobe on, active state HIGH or LOW
- static const bool STROBE_OFF; //logic level of strobe off, complement of active state
- const uint8_t strobePin; //Arduino pin number connected to this row
- const uint8_t byte_count; //number of bytes to read from shift registers
- public:
- Scanner_ShiftRegs74HC165(const uint8_t strobePin, const uint8_t readPinCount);
- virtual read_pins_t scan();
- void begin();
- };
- #endif
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