// Written by Stefan Grimm, 2021.
// Released into the public domain.
//
#include <SoftwareSerial.h>
#include "Adafruit_MCP23008.h"

// MCP expander pins
const uint8_t Pin_A = 7;
const uint8_t Pin_B = 6;
const uint8_t Pin_C = 5;
const uint8_t Pin_D = 4;
const uint8_t Pin_E = 0;
const uint8_t Pin_M0 = 1;
const uint8_t Pin_M1 = 2;

// Arduino pins
const uint8_t Pin_C1 = 10;
const uint8_t Pin_C2 = 9;
const uint8_t Pin_C3 = 6;
const uint8_t Pin_C4 = 5;

const uint8_t Usb_YEL = 11;
const uint8_t Usb_ORA = 12;

typedef SoftwareSerial Logger_t;
Logger_t logger(Usb_ORA, Usb_YEL);
Adafruit_MCP23008 mcp;
  
void setup() {
  for (int n=0; n<50 && !Serial; n++) {
    delay(100);
  }
  Serial.begin(9600);
  logger.begin(9600);
  
  mcp.begin();
  mcp.pinMode(Pin_A, INPUT); mcp.pullUp(Pin_A, HIGH);
  mcp.pinMode(Pin_B, INPUT); mcp.pullUp(Pin_B, HIGH);
  mcp.pinMode(Pin_C, INPUT); mcp.pullUp(Pin_C, HIGH);
  mcp.pinMode(Pin_D, INPUT); mcp.pullUp(Pin_D, HIGH);
  mcp.pinMode(Pin_E, INPUT); mcp.pullUp(Pin_E, HIGH);
  mcp.pinMode(Pin_M0, INPUT); mcp.pullUp(Pin_M0, HIGH);
  mcp.pinMode(Pin_M1, INPUT); mcp.pullUp(Pin_M1, HIGH);
  
  ::pinMode(Pin_C1, INPUT_PULLUP);
  ::pinMode(Pin_C2, INPUT_PULLUP);
  ::pinMode(Pin_C3, INPUT_PULLUP);
  ::pinMode(Pin_C4, INPUT_PULLUP);
}

void loop() {
  if (mcp.digitalRead(Pin_A) == LOW) {
    Serial.println("Btn_A");
    logger.println("Btn_A");
  }
  if (mcp.digitalRead(Pin_B) == LOW) {
    Serial.println("Btn_B");
    logger.println("Btn_B");
  }
  if (mcp.digitalRead(Pin_C) == LOW) {
    Serial.println("Btn_C");
    logger.println("Btn_C");
  }
  if (mcp.digitalRead(Pin_D) == LOW) {
    Serial.println("Btn_D");
    logger.println("Btn_D");
  }
  if (mcp.digitalRead(Pin_E) == LOW) {
    Serial.println("Btn_E");
    logger.println("Btn_E");
  }
  if (mcp.digitalRead(Pin_M0) == LOW) {
    Serial.println("Sw_M0");
    logger.println("Sw_M0");
  }
  if (mcp.digitalRead(Pin_M1) == LOW) {
    Serial.println("Sw_M1");
    logger.println("Sw_M1");
  }
  if (::digitalRead(Pin_C1) == HIGH) {
    Serial.println("Code_1");
    logger.println("Code_1");
  }
  if (::digitalRead(Pin_C2) == HIGH) {
    Serial.println("Code_2");
    logger.println("Code_2");
  }
  if (::digitalRead(Pin_C3) == HIGH) {
    Serial.println("Code_3");
    logger.println("Code_3");
  }
  if (::digitalRead(Pin_C4) == HIGH) {
    Serial.println("Code_4");
    logger.println("Code_4");
  }
  delay(500);  
}