1 files changed, 45 insertions, 0 deletions
diff --git a/MCP23017/MCP23017.ino b/MCP23017/MCP23017.ino
new file mode 100644
index 0000000..30c75bc
--- /dev/null
+++ b/MCP23017/MCP23017.ino
@@ -0,0 +1,45 @@
+//https://tronixstuff.com/2011/08/26/arduino-mcp23017-tutorial/
+//https://www.circuitbasics.com/how-to-use-an-mpc23017-port-expander-on-the-arduino/
+//https://ww1.microchip.com/downloads/en/devicedoc/20001952c.pdf
+
+
+
+#include <Wire.h> 
+byte BbyteVal=0;
+byte AbyteVal=0;
+byte chipAddr = 0x20;
+byte GPIOA = 0x12; // PortA reg addr
+byte GPIOB = 0x13; // PortB reg addr
+byte IODIRA = 0x00; // PortA direction reg addr
+byte IODIRB = 0x01; // PortB direction reg addr
+
+void setup(){
+  Serial.begin(9600);
+  Wire.begin();
+  
+  Wire.beginTransmission(chipAddr);
+  Wire.write(IODIRA); // IODIRA dir register
+  Wire.write(0xff); // set entire PORT A  as output
+  Wire.endTransmission();
+
+  Wire.beginTransmission(chipAddr);
+  Wire.write(IODIRB); // IODIRB dir register
+  Wire.write(0xff); // set entire PORT B as input
+  Wire.endTransmission();
+  }
+
+void loop(){    
+  Wire.beginTransmission(chipAddr);
+  Wire.write(GPIOB);  // read the inputs off PORT B
+  Wire.requestFrom(chipAddr, 1); // ask for 1 byte
+  BbyteVal = Wire.read(); // read it
+  Wire.endTransmission();
+  Serial.println(BbyteVal);
+
+  Wire.beginTransmission(chipAddr);
+  Wire.write(GPIOB);  // read the inputs off PORT B
+  Wire.requestFrom(chipAddr, 1); // ask for 1 byte
+  AbyteVal = Wire.read(); // read it
+  Wire.endTransmission();
+  Serial.println(AbyteVal);
+}