TCA6416A 从机地址是多少?读写位怎么处理?
时间:10-02
整理:3721RD
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我看官方提供的430操作该器件发送的从机地址是7位(0x20)
/************************** I2C Address ***************************************/ #define TCA6416A_ADDRESS 0x20 // I2C Address 0100 00 + ADDR + R/W // ADDR tied to P2.2 of LaunchPad /************************** I2C Registers *************************************/
然后
// **************************************************************************** //! @fn void TCA6416AInitI2CReg(TCA6416ARegs* Regs) //! @brief //! //! TODO Implement I2C return (success/failure) // **************************************************************************** unsigned char TCA6416AInitI2CReg(TCA6416ARegs* Regs){ unsigned char return_Value = I2C_OPERATION_SUCCESSFUL; I2C_Write(2, TCA6416A_ADDRESS, TCA6416A_CONFIG_REG0, (unsigned char*)&Regs->Config, 0); I2C_Write(2, TCA6416A_ADDRESS, TCA6416A_OUTPUT_REG0, (unsigned char*)&Regs->Output, 0); I2C_Write(2, TCA6416A_ADDRESS, TCA6416A_POLARITY_REG0, (unsigned char*)&Regs->PolarityInversion, 0); if(NACK) { NACK = 0; return_Value = I2C_OPERATION_FAIL; } return return_Value; }
然后
void I2C_Write (unsigned char byte_Count, unsigned char Slave_Address, unsigned char Register_Address, unsigned char Register_Data[], unsigned char offset) { // wait until I2C module has finished all operations. while (UCB0STAT & UCBUSY); // Set slave address UCB0I2CSA = Slave_Address; I2CBufferArray[byte_Count] = Register_Address; // If word mode, write 2 bytes int x = byte_Count-1; unsigned char y=0; for (;x>=0;x--) { I2CBufferArray[x] = Register_Data[y+offset]; y++; } PtrTransmit = byte_Count; // start condition generation I2CWriteInit(); // => I2C communication is started UCB0CTL1 |= UCTXSTT; UCB0I2CIE |= UCNACKIE; // Enter LPM0 w/ interrupts __bis_SR_register(LPM0_bits + GIE); // I2C stop condition UCB0CTL1 |= UCTXSTP; // Ensure stop condition got sent while(UCB0CTL1 & UCTXSTP); UCB0I2CIE &= ~UCNACKIE; }
UCB0I2CSA = Slave_Address;
从上面这句话可以看出访问TCA6416A就是这个,那个R/W#位怎么使用的。
I2C Address格式就是后面注释部分,7位从机地址加一位读写位, 对于TCA6416A来说,为0100 00 + ADDR + R/W,ADDR 通过ADDR引脚的高低电平来决定,读写位为方向位,写为0,1为读。
嗯,谢谢,意思是说MSP430的知道的是7位从机地址,然后读写位是由430中某位寄存器决定,然后通过硬件自动加上去的。如果我模拟IIC的话就需要直接发送8位地址。
读写位是由数据方向控制的,如果主机向从机发送数据,就是写为0, 主机读从机中的数据就为1.
而在调用函数时,只需要将从机的7位地址填写进去即可,正如这里的430发送的地址为0x20,即7位地址,0100000