ラズパイpicoにMCP23017を繋いでI/Oを16ポート増設

#include <Wire.h>
#include <MCP23017.h>

#define MCP23017_ADDR 0x20
MCP23017 mcp = MCP23017(MCP23017_ADDR);

void setup()
{
　Wire.setSDA(20); //GP20
　Wire.setSCL(21); //Gp21
　Wire.begin();
　pinMode(LED_BUILTIN, OUTPUT);
　digitalWrite(LED_BUILTIN, HIGH);

　Serial.begin(115200);
　while (!Serial); // wait for serial monitor
　Serial.println("\n Test program for the MCP23017\n");

　mcp.init();
　mcp.portMode(MCP23017Port::A, 0); //Port A as output
　mcp.portMode(MCP23017Port::B, 0); //Port B as output
　mcp.writeRegister(MCP23017Register::GPIO_A, 0x00); //Reset port A
　mcp.writeRegister(MCP23017Register::GPIO_B, 0x00); //Reset port B
}

void loop() {
　mcp.writePort(MCP23017Port::A, 0xff);
　mcp.writePort(MCP23017Port::B, 0x00);

　delay(500);
　Serial.print(".");
　digitalWrite(LED_BUILTIN, LOW);

　mcp.writePort(MCP23017Port::A, 0x00);
　mcp.writePort(MCP23017Port::B, 0xff);

　delay(500);
　digitalWrite(LED_BUILTIN, HIGH);
}