AVR 下用Arduino操作I2C

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<p>// Send control and register address bytes</p><p>Wire.beginTransmission(0x20);</p><p>Wire.write(0x00);</p><p>// Write data to IODIRA register</p><p>Wire.write(0xFF);</p><p>// End session</p><p>Wire.endTransmission();</p><p>// Send control and register address bytes</p><p>Wire.beginTransmission(0x20);</p><p>Wire.write(0x12); // GPIOA</p><p>Wire.endTransmission();</p><p>// Read data from port A</p><p>Wire.requestFrom(0x20, 1); // set R/W bit to 1 (read)</p><p>portval = Wire.read(); // still points to 0x12</p><p>Since the GP I/O ports are configured as inputs by default at power-up or after a reset</p><p>(see Table 10-9), the first step could have been omitted. To configure the port as an</p><p>output the IODIRA bits would be set to 0. This is shown in the code snippet in</p><p>Example 10-8.</p><p>Example 10-8. Writing data to the output port</p><p>// Send control and register address bytes</p><p>Wire.beginTransmission(0x20);</p><p>Wire.write(0x00);</p><p>// Write data to IODIRA register</p><p>Wire.write(0x0);</p><p>// End</p><p>Wire.endTransmission();</p><p>// Send control and register address bytes</p><p>Wire.beginTransmission(0x20);</p><p>Wire.write(0x12); // GPIOA</p><p>// Write data to port A</p><p>Wire.write(portval);</p><p>Wire.endTransmission();</p>

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// Send control and register address bytes

Wire.beginTransmission(0x20);

Wire.write(0x00);

// Write data to IODIRA register

Wire.write(0xFF);

// End session

Wire.endTransmission();

// Send control and register address bytes

Wire.beginTransmission(0x20);

Wire.write(0x12); 

// GPIOA

Wire.endTransmission();

// Read data from port A

Wire.requestFrom(0x20, 1); 

// set R/W bit to 1 (read)

portval = Wire.read(); 

// Send control and register address bytesWire.beginTransmission(0x20);

Wire.write(0x00);

// Write data to IODIRA register

Wire.write(0x0);

// EndWire.endTransmission();

// Send control and register address bytes

Wire.beginTransmission(0x20);

Wire.write(0x12); 

// GPIOA

// Write data to port A

Wire.write(portval);

Wire.endTransmission();

乱了，帮你修改下。

这个用Arduino多啊

Arduino还是简单一些，但是好像那个环境下不能单步调试

好乱的格式

还是arduino用的多啊