http://forums.leaflabs.com/topic.php?id=1146 A place to share, learn, and grow... en-US Fri, 22 Jan 2016 00:25:45 +0000 http://bbpress.org/?v=1.0.2 q http://forums.leaflabs.com/search.php http://forums.leaflabs.com/topic.php?id=1146#post-7061 Tue, 01 Nov 2011 03:38:10 +0000 Farid 7061@http://forums.leaflabs.com/ <p>Is the delay time is right?<br /> #define I2C_DELAY do{for(int i=0;i&lt;50;i++) {asm volatile("nop");}}while(0)<br /> If we use this delay time ,what's the clock fre? </p> http://forums.leaflabs.com/topic.php?id=1146#post-7060 Mon, 31 Oct 2011 20:37:40 +0000 Farid 7060@http://forums.leaflabs.com/ <p>I want to use the I2C to communicate,This is my code:<br /> uint8 TwoWire::readregister(uint8 slave_addr,uint8 reg_addr, uint8 *value) {<br /> uint8 ret = SUCCESS;<br /> if(0 == i2c_init_flag){<br /> Wire.begin();<br /> i2c_init_flag = 1;<br /> }</p> <p> i2c_start(port);<br /> i2c_shift_out(port, (slave_addr &lt;&lt; 1) | I2C_WRITE);<br /> if (!i2c_get_ack(port)) return ENACKADDR;<br /> ret = writeOneByte(reg_addr);<br /> if (ret) return ret; // SUCCESS is 0<br /> ret= readOneByte(slave_addr, value);</p> <p> return(ret);</p> <p>}</p> <p>But when I use this fucntion like this to test the I2C:</p> <p>#define DEV_I2C_ADDR 0x18 //0 0 1 1 0 0 X</p> <p>void test_I2C()<br /> {<br /> uint8 value = 0xff;<br /> if(SUCCESS == Wire.readregister(DEV_I2C_ADDR, 0x0C, &amp;value)){<br /> SerialUSB.print("I2CVALUE=0x");<br /> SerialUSB.println(value,HEX);<br /> SerialUSB.print("\r\n");<br /> }else {<br /> SerialUSB.print("Read error....");<br /> SerialUSB.print("\r\n");<br /> }</p> <p> Omni.delayMS(1000);</p> <p>}<br /> The SerialUSB just ouput:I2CVALUE=0x0<br /> So, anyone can tell me why the result is 0x0?Is my function write correct？</p> <p>Many thanks！ </p>