1234567891011121314151617181920212223242526272829303132333435363738394041424344 |
- #ifndef ROWSCANNER_SPI_SHIFTREGISTERS_H
- #define ROWSCANNER_SPI_SHIFTREGISTERS_H
- #include <Arduino.h>
- #include <inttypes.h>
- #include <SPI.h>
- #include <RowScannerInterface.h>
- #include <RowPort.h>
- #include <ColPort.h>
-
- /* RowScanner_SPIShiftRegisters reads all shift registers in a daisy chain.
- The maximum keys per row is 31, because Arduino's largest type is 32 bits and rowEnd consumes the last bit.
- //todo delete: Assumes only one row of shift registers is connected (no Slave Select).
-
- For active low:
- 10k pull-up resistor are connected to power
- connect controller's MISO pin to shift register's /QH pin
- in sketch, const bool RowScanner_PinsArray::ACTIVE_HIGH = 0;
-
- For active high:
- 10k pull-down resistors are grounded
- connect controller's MISO pin to shift register's QH pin
- in sketch, const bool RowScanner_PinsArray::ACTIVE_HIGH = 1;
-
- shift registers 74HC165 Parallel-In-Serial-Out (PISO) are Daisy chained
-
- The maximum keys per row is 31, because Arduino's largest type is 32 bits and rowEnd consumes the last bit.
- call begin() from setup()
-
- */
- class RowScanner_SPIShiftRegisters : public RowScannerInterface
- {
- private:
- //todo static const bool ACTIVE_HIGH; //logic level of strobe pin: 0=activeLow, 1=activeHigh
- static const uint8_t SHIFT_LOAD; //controller's pin number that is connected to shift register's SHIFT_LOAD pin
- const uint8_t STROBE_PIN; //Arduino pin number connected to this row
- const uint8_t KEY_COUNT; //number of keys in row
- const uint8_t BYTE_COUNT; //number of bytes to read from shift registers
- public:
- RowScanner_SPIShiftRegisters(const uint8_t STROBE_PIN, uint8_t KEY_COUNT)
- : STROBE_PIN(STROBE_PIN), KEY_COUNT(KEY_COUNT), BYTE_COUNT(ceil (float(KEY_COUNT)/8)) {}
- virtual read_pins_t scan(read_pins_mask_t& rowEnd);
- void begin();
- };
- #endif
|