#include "PortMCP23S17.h" /* transfer() writes data to registerAddr, reads portSate from registerAddr, and returns portState. */ uint8_t PortMCP23S17::transfer(const uint8_t command, const uint8_t registerAddr, const uint8_t data) { uint8_t portState; //bit pattern digitalWrite(SS, LOW); //enable Slave Select SPI.transfer(command); //write or read command SPI.transfer(registerAddr); //register address to write data to portState = SPI.transfer(data); //write data, read portState digitalWrite(SS, HIGH); //disable Slave Select return portState; } /* begin() is called from Scanner_IOE::begin(). Initiates SPI bus and configures I/O pins for read and write. strobeOn is logic level of strobe on, HIGH or LOW MCP23S17 SPI interface is 10 MHz max. The electrical limitation to bus speed is bus capacitance and the length of the wires involved. Longer wires require lower clock speeds. */ void PortMCP23S17::begin(const uint8_t strobeOn) { uint8_t pullUp; //bits, GPPU 0=pull-up disabled, 1=pull-up enabled pinMode(SS, OUTPUT); //configure controller's Slave Select pin to output digitalWrite(SS, HIGH); //disable Slave Select SPI.begin(); SPI.beginTransaction(SPISettings (5000000, MSBFIRST, SPI_MODE0)); //control SPI bus, 5 MHz //SPI.endTransaction() not called to release SPI bus because keyboard only has one SPI device if (strobeOn == LOW) //if active low, use internal pull-up resistors { pullUp = readPins; } else //active high requires external pull-down resistors { pullUp = 0; } //todo Keyboard.print(" strobeOn="); Keyboard.print(strobeOn); Keyboard.print(" readPins="); Keyboard.print(readPins, BIN); Keyboard.print(" pullUp="); Keyboard.println(pullUp, BIN); transfer(port.DEVICE_ADDR << 1, port.num, readPins); //configure IODIR transfer(port.DEVICE_ADDR << 1, port.num + 0x0C, pullUp); //configure GPPU } /* write() sets pin output to logicLevel (useful for strobePin, one LED pin, or multiple pins). pin is bit pattern, where pin being set is 1. logicLevel is HIGH or LOW. write() does not overwrite the other pins. */ void PortMCP23S17::write(const uint8_t pin, const bool logicLevel) { if (logicLevel == LOW) { port.outputVal &= ~pin; //set pin output to low } else { port.outputVal |= pin; //set pin output to high } //todo //Keyboard.print(" readPins="); Keyboard.print(readPins, BIN); Keyboard.print(" pin="); Keyboard.print(pin, BIN); Keyboard.print(" logicLevel="); Keyboard.print(logicLevel); Keyboard.print(" outputVal="); Keyboard.println(port.outputVal, BIN); //Keyboard.print(" ="); Keyboard.print(); //delay(200); transfer(port.DEVICE_ADDR << 1, port.num + 0x12, port.outputVal); //set GPIO port to outputVal } /* read() returns portState. Only portState pins with pull resistors are valid. */ uint8_t PortMCP23S17::read() { return transfer( (port.DEVICE_ADDR << 1) | 1, port.num + 0x12, 0); //read from GPIO }