arduinoでi2c その２

概要

arduinoでi2cやってみた。
twi.h使って、i2cスキャナー、やってみた。

写真

回路図

サンプルコード

extern "C" {
# include <stdlib.h>
# include <string.h>
# include <inttypes.h>
# include "twi.h"
}
uint8_t rxBuffer[32];
uint8_t rxBufferIndex = 0;
uint8_t rxBufferLength = 0;
uint8_t txAddress = 0;
uint8_t txBuffer[32];
uint8_t txBufferIndex = 0;
uint8_t txBufferLength = 0;

void i2c_start(uint8_t address)
{
	twi_init();
	txAddress = address;
}
uint8_t i2c_stop(uint8_t sendStop)
{
	int8_t ret = twi_writeTo(txAddress, txBuffer, txBufferLength, 1, sendStop);
	return ret;
}
void setup()
{
	char outdata;
	outdata = 0x09;
	Serial.begin(115200);
	Serial.println("\nI2C Scanner");
	byte error = 1;
	byte address;
	int nDevices = 0;
	Serial.println("Scanning...");
	for (address = 1; address < 127; address++)
	{
		i2c_start(address);
		error = i2c_stop(true);
		if (error == 0)
		{
			Serial.print("I2C device found at address 0x");
			if (address < 16) Serial.print("0");
			Serial.print(address, HEX);
			Serial.println("  !");
			nDevices++;
		}
		else if (error == 4)
		{
			Serial.print("Unknow error at address 0x");
			if (address < 16) Serial.print("0");
			Serial.println(address, HEX);
		}
	}
	if (nDevices == 0) Serial.println(" No I2C devices found\n");
	else Serial.println("done\n");
	Serial.println("ok");
}
void loop()
{
	delay(100);
}

結果

I2C Scanner
Scanning...
I2C device found at address 0x27  !
done

ok

以上。