GPIO编程模拟I2C入门

﹏ヽ暗。殇╰゛Y 2022-06-17 23:59 228阅读 0赞

ARM编程:ARM普通GPIO口线模拟I2C  
![None.gif][]  
![None.gif][]请教个问题：  
![None.gif][]因为需要很多EEPROM进行点对点控制，所以我现在要用ARM的GPIO模拟I2C，管脚方向我设  
![None.gif][]置的是向外的。我用网上的RW24C08的万能程序修改了一下，先进行两根线的模拟，SDA6，  
![None.gif][]SCL6，但是读出来的数不对。我做了一个简单的实验，模拟SDA6，SCL6输出方波，在示波  
![None.gif][]器上看到正确方波，也就是说，我的输出控制是没问题的。  
![None.gif][]哪位大哥能指点一下，是否在接收时管脚方向要设为向内？（不过IOPIN不管什么方向都可  
![None.gif][]以读出当前状态值的阿）  
![None.gif][]  
![None.gif][]附修改的RW24C08()程序：  
![None.gif][]\#define SomeNOP() delay(300);  
![ExpandedBlockStart.gif][]/\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\* RW24C08  
![ExpandedBlockEnd.gif][]\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*/  
![ExpandedBlockStart.gif][]/\*\-----------------------------------------------------------------------------  
![InBlock.gif][]\---  
![InBlock.gif][] 调用方式：void I2CInit(void)  
![InBlock.gif][] 函数说明：私有函数，I2C专用  
![InBlock.gif][]\-------------------------------------------------------------------------------  
![ExpandedBlockEnd.gif][]\--\*/  
![None.gif][]void I2CInit(void)  
![ExpandedBlockStart.gif][]\{  
![InBlock.gif][] IO0CLR = SCL6; //初始状态关闭总线  
![InBlock.gif][] SomeNOP(); //延时   
![InBlock.gif][] I2CStop(); //确保初始化，此时数据线是高电平  
![ExpandedBlockEnd.gif][]\}  
![None.gif][]  
![ExpandedBlockStart.gif][]/\*\----------------------------------------------------------------------------  
![InBlock.gif][]\----  
![InBlock.gif][] 调用方式：void I2CStart(void)  
![InBlock.gif][] 函数说明：私有函数，I2C专用  
![InBlock.gif][]\-------------------------------------------------------------------------------  
![ExpandedBlockEnd.gif][]\--\*/  
![None.gif][]void I2CStart(void)  
![ExpandedBlockStart.gif][]\{  
![InBlock.gif][]  
![InBlock.gif][] SomeNOP();  
![InBlock.gif][] IO0SET = SCL6;  
![InBlock.gif][] SomeNOP();//INI  
![InBlock.gif][] IO2CLR = SDA6;  
![InBlock.gif][] SomeNOP(); //START  
![InBlock.gif][] IO0CLR = SCL6;  
![InBlock.gif][] SomeNOP();  
![ExpandedBlockEnd.gif][]\}  
![ExpandedBlockStart.gif][]/\*\-----------------------------------------------------------------------------  
![InBlock.gif][]\---  
![InBlock.gif][] 调用方式：void I2CStop(void)  
![InBlock.gif][] 函数说明：私有函数，I2C专用  
![InBlock.gif][] \------------------------------------------------------------------------------  
![ExpandedBlockEnd.gif][]\---\*/  
![None.gif][]void I2CStop(void)  
![ExpandedBlockStart.gif][]\{  
![InBlock.gif][] IO2CLR = SDA6;  
![InBlock.gif][] SomeNOP(); //INI  
![InBlock.gif][] IO0SET = SCL6;  
![InBlock.gif][] SomeNOP();  
![InBlock.gif][] IO2SET = SDA6;  
![InBlock.gif][] SomeNOP();  
![InBlock.gif][] IO0CLR = SCL6;  
![ExpandedBlockEnd.gif][] \}  
![None.gif][]  
![None.gif][]  
![ExpandedBlockStart.gif][]/\*\+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++  
![InBlock.gif][]I2CClock: 发送总线时钟信号，并返回时钟电平为高期间SDA上的状态，低为 ACK，高失败  
![ExpandedBlockEnd.gif][]\++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++\*/  
![None.gif][]  
![None.gif][]INT8U I2CClock(void)  
![ExpandedBlockStart.gif][]\{  
![InBlock.gif][] INT8U sample;  
![InBlock.gif][] SomeNOP();  
![InBlock.gif][] IO0SET = SCL6;  
![InBlock.gif][] delay(180);  
![InBlock.gif][] sample = (INT8U)((IO2PIN &0x2000)>>13);  
![InBlock.gif][] delay(120);  
![InBlock.gif][] IO0CLR = SCL6;  
![InBlock.gif][] SomeNOP();  
![InBlock.gif][]//return (sample);  
![InBlock.gif][]if(sample==1) return(1);  
![InBlock.gif][]elsereturn(0);  
![ExpandedBlockEnd.gif][]\}  
![ExpandedBlockStart.gif][]/\*\-----------------------------------------------------------------------------  
![InBlock.gif][]\---  
![InBlock.gif][] 调用方式：void SendAck(void)  
![InBlock.gif][] 函数说明：私有函数，I2C专用，主器件为接收方，从器件为发送方时，应答信号。  
![InBlock.gif][] \------------------------------------------------------------------------------  
![ExpandedBlockEnd.gif][]\---\*/  
![None.gif][]void SendAck(void)  
![ExpandedBlockStart.gif][]\{  
![InBlock.gif][] IO2CLR = SDA6;  
![InBlock.gif][] I2CClock();  
![InBlock.gif][] IO2SET = SDA6;  
![ExpandedBlockEnd.gif][] \}  
![None.gif][]  
![ExpandedBlockStart.gif][]/\*\----------------------------------------------------------------------------  
![InBlock.gif][]\----  
![InBlock.gif][] 调用方式：void SendAck(void)  
![InBlock.gif][] 函数说明：私有函数，I2C专用，主器件为接收方，从器件为发送方时，非应答信号。  
![InBlock.gif][]\*\*-----------------------------------------------------------------------------  
![ExpandedBlockEnd.gif][]\---\*/  
![None.gif][]void SendNotAck(void)  
![ExpandedBlockStart.gif][]\{  
![InBlock.gif][] IO2SET = SDA6;  
![InBlock.gif][] I2CClock();  
![ExpandedBlockEnd.gif][] \}  
![None.gif][]  
![ExpandedBlockStart.gif][]/\*\----------------------------------------------------------------------------  
![InBlock.gif][]\----  
![InBlock.gif][] 调用方式：void I2CSend(uchar ch)  
![InBlock.gif][] 函数说明：私有函数，I2C专用  
![InBlock.gif][] \------------------------------------------------------------------------------  
![ExpandedBlockEnd.gif][]\---\*/  
![None.gif][]INT8U I2CSendByte(INT8U ch)  
![ExpandedBlockStart.gif][]\{  
![InBlock.gif][] register INT8U i;  
![InBlock.gif][] INT8U statue;  
![ExpandedSubBlockStart.gif][]for (i=0; i<8; i\++)\{  
![InBlock.gif][] statue = (INT8U) ((ch&0x80)>>7);  
![InBlock.gif][]if(statue==1)  
![InBlock.gif][] IO2SET = SDA6;  
![InBlock.gif][]else  
![InBlock.gif][] IO2CLR = SDA6;  
![InBlock.gif][] ch <<=1;  
![InBlock.gif][] I2CClock();  
![ExpandedSubBlockEnd.gif][] \}  
![InBlock.gif][] IO2SET = SDA6;  
![InBlock.gif][]return (~I2CClock());  
![ExpandedBlockEnd.gif][] \}  
![None.gif][]  
![ExpandedBlockStart.gif][]/\*\----------------------------------------------------------------------------  
![InBlock.gif][]\----  
![InBlock.gif][] 调用方式：uchar I2CReceive(void)  
![InBlock.gif][] 函数说明：私有函数，I2C专用  
![InBlock.gif][] \------------------------------------------------------------------------------  
![ExpandedBlockEnd.gif][]\---\*/  
![None.gif][]INT8U I2CReceiveByte(void)  
![ExpandedBlockStart.gif][]\{  
![InBlock.gif][] register INT8U i;  
![InBlock.gif][] INT8U ddata=0;  
![ExpandedSubBlockStart.gif][]for (i=0;i<8;i\++)\{  
![InBlock.gif][] ddata<<=1;  
![InBlock.gif][]if(I2CClock()) ddata\++;  
![ExpandedSubBlockEnd.gif][] \}  
![InBlock.gif][]return (ddata);  
![ExpandedBlockEnd.gif][] \}  
![None.gif][]  
![ExpandedBlockStart.gif][]/\*\------------------------------------------------  
![InBlock.gif][]RW2408 Function  
![ExpandedBlockEnd.gif][]\------------------------------------------------\*/  
![None.gif][]//DataBuff 为读写数据输入／输出缓冲区的首址  
![None.gif][]//Length 为要读写数据的字节数量  
![None.gif][]//Address 为EEPROM的片内地址  
![None.gif][]//ControlByte 为EEPROM的控制字节，具体形式为(1)(0)(1)(0)(A2)(A1)(A0)(R/W),  
![None.gif][]// 其中R/W=1,表示读操作,R/W=0为写操作,A2,A1,A0为EEPROM的页选或片选  
![None.gif][]地址;  
![None.gif][]void RW2408(INT8U \*DataBuff,INT8U Length,INT32U Addr,INT8U Wr)  
![ExpandedBlockStart.gif][]\{  
![InBlock.gif][] INT8U j; // 发送字节索引  
![InBlock.gif][]// EA=0; // 发送期间禁止中断，防止  
![InBlock.gif][]干扰  
![InBlock.gif][] I2CInit();  
![InBlock.gif][] I2CStart(); // 启动总线   
![InBlock.gif][] I2CSendByte(0xa0); // 向IIC总线发送2408写地址  
![InBlock.gif][] I2CSendByte(Addr); // 向IIC总线发送要操作的RAM  
![InBlock.gif][]地址  
![InBlock.gif][]  
![InBlock.gif][]if(Wr==0) // 如果是写操作   
![ExpandedSubBlockStart.gif][]\{  
![InBlock.gif][]for(j=0;j<Length;j\++)  
![ExpandedSubBlockStart.gif][]\{  
![InBlock.gif][] I2CSendByte(\*DataBuff\++); // 每个循环送1个数据  
![ExpandedSubBlockEnd.gif][] \}  
![ExpandedSubBlockEnd.gif][] \}  
![ExpandedSubBlockStart.gif][]/\*\---------------------------如果是读操作 ----------------------\*/  
![InBlock.gif][]elseif(Wr==1)  
![ExpandedSubBlockStart.gif][]\{  
![InBlock.gif][] I2CStart(); // 启动总线   
![InBlock.gif][] I2CSendByte(0xa1); // 向IIC总线发送2408读地址  
![InBlock.gif][]  
![InBlock.gif][]for(j=0;j<Length\-1;j\++)  
![ExpandedSubBlockStart.gif][]\{  
![InBlock.gif][] IO2SET = SDA6; // 写之前把数  
![InBlock.gif][]据线置高  
![InBlock.gif][]\*DataBuff\++=I2CReceiveByte(); // 每次读1个字节  
![InBlock.gif][] SendAck(); // 发送应答信号   
![ExpandedSubBlockEnd.gif][] \}  
![InBlock.gif][]\*DataBuff=I2CReceiveByte(); // 读最后一个数据  
![InBlock.gif][] SendNotAck(); // 发送非应答信号   
![ExpandedSubBlockEnd.gif][] \}  
![InBlock.gif][] I2CStop(); // 停止IIC总线  
![InBlock.gif][]// EA=1;  
![ExpandedBlockEnd.gif][]\}

[None.gif]: /images/20220618/f7cdfe8714e448e0846d84774d012511.png
[ExpandedBlockStart.gif]: /images/20220618/05e7ff26d9f34f05b4d08169bb8afa29.png
[ExpandedBlockEnd.gif]: /images/20220618/5b96049f5f784ca59ef96f011fa27713.png
[InBlock.gif]: /images/20220618/04ced6177c0d4c099f2989916ecc398d.png
[ExpandedSubBlockStart.gif]: /images/20220618/5d037a5f151f427d9547df344f79a517.png
[ExpandedSubBlockEnd.gif]: /images/20220618/04b9f58689634a8493c51aa43f6510a0.png