msp430单片机模拟IIC总线读取MMA7660三轴加速度传感器
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搞了几天的msp430单片机，发现它的硬件IIC并不是很好用（没调出来，嘿嘿），所以就弃之不用了，改用模拟IIC总线的协议。用来读取MMA7660三轴加速度按传感器的X，Y，Z的值，并通过串口显示出来，串口也是通过定时器TimerA模拟来的，只是为了练习一下单片机的编程所以都用了模拟。测试结果如下：
main.c #include "msp430G2452.h" #include "g2452uart.h" #include "MMA7660FC.h" #define SDA_DirOut P2DIR |= BIT0 #define SDA_DirIn P2DIR &=~ BIT0 #define SDA_0 P2OUT &=~ BIT0 #define SDA_1 P2OUT |= BIT0 #define SCL_1 P2OUT |= BIT1 #define SCL_0 P2OUT &=~ BIT1 #define Get_Bit( x,y) ((x&(1<<y))==0? 0="" :="" 1="" ) #define SDA_in Get_Bit(P2IN,0) char X_value=0 ; char Y_value=0 ; char Z_value=0 ; signed char X_value_final,Y_value_final,Z_value_final; //三轴加速度的最终值，有正负 void OSC_Init() { WDTCTL=WDTPW+WDTHOLD;//close whatchdog if (CALBC1_1MHZ ==0xFF || CALDCO_1MHZ == 0xFF) { while(1); // If calibration constants erased // do not load, trap CPU!! } //1Mhz BCSCTL1 = CALBC1_1MHZ; // Set range DCOCTL = CALDCO_1MHZ; // Set DCO step + modulation */ } void Port_Init() { P2DIR |= BIT0+BIT1; SDA_1; SCL_1; } void delay_us( unsigned int k ) { while(k--) _nop(); } void IIC_Start() { SDA_1; SCL_1; delay_us(5); SDA_0; //产生下降沿 delay_us(5); SCL_0; //拉低时钟线，准备发送或者接收数据 } void IIC_Stop() { SCL_1; SDA_0; delay_us(5); SDA_1; //产生一个上升沿 delay_us(5); } void IIC_SendAck() { SDA_0; SCL_1; delay_us(5); SCL_0; delay_us(5); } void IIC_SendNAck() { SDA_1; SCL_1; delay_us(5); SCL_0; delay_us(5); } unsigned char IIC_RecAck() { unsigned char CY ; SDA_DirIn; //在接收模式下，设置SDA的方向为输入 SCL_1; //拉高时钟线 delay_us(5); //延时 CY = SDA_in; //读应答信号 SCL_0 ; //拉低时钟线 delay_us(5); //延时 SDA_DirOut; //接收结束的时候还要吧SDA的方向切换过来 return CY; } void IIC_WriteByte(unsigned int data) { unsigned char i ; for (i=0;i<8;i++) { if((data&0x80)?1:0) //分别发送每一位二进制数据 SDA_1; else SDA_0 ; SCL_1; data<<=1; //移位传送下一位 delay_us(5); SCL_0; //在SCL上升沿的时候加载一位的数据 delay_us (5); } SDA_1; //8位数据位发送完释放数据总线，同时ＳＤＡ拉高 // IIC_Recevie(); //接收答信号 } unsigned char IIC_Read(void ) { unsigned char i ,data=0; SDA_DirIn; //在接收模式下，设置SDA的方向为输入 for (i=0;i<8;i++) { SCL_0; delay_us(5); SCL_1 ; //SCL下降沿期间有数据，当SCL为高时数据线上的数据才有效 data<<=1; data|=SDA_in; delay_us(3); } SDA_DirOut; //接收结束的时候还要吧SDA的方向切换过来 return data; } void WriteToAddr(unsigned char REG_addr, unsigned char REG_data ) { IIC_Start(); IIC_WriteByte(SlaveAddress+0); //发送从机地址+写入操作0 IIC_RecAck(); //应答 IIC_WriteByte(REG_addr); //写入内部寄存器地址 IIC_WriteByte(REG_data); //写入内部寄存器数据 IIC_RecAck(); IIC_Stop(); delay_us(5); } unsigned char ReadFromAddr(unsigned char REG_addr) { unsigned char RecData ; IIC_Start(); //启动IIC总线 IIC_WriteByte(SlaveAddress+0); //写入从机地址+写命令0 IIC_WriteByte(REG_addr); //写入要读的内部寄存器地址 IIC_Start(); IIC_WriteByte(SlaveAddress+1); //写入从机地址+读命令1 RecData=IIC_Read(); IIC_SendNAck(); IIC_Stop(); return RecData; } void MMA7660_Init() { WriteToAddr(MMA7660_MODE,0x01); } void Read3axle(void) { X_value=ReadFromAddr(X_outAddr); Y_value=ReadFromAddr(Y_outAddr); Z_value=ReadFromAddr(X_outAddr); //将采集到的数据转换到-32~31之间 X_value_final=(char)(X_value<<2); X_value_final =(char)(X_value_final /4); Y_value_final= (char)(Y_value<<2); Y_value_final = (char)(Y_value_final /4); Z_value_final= (char)(Z_value<<2); Z_value_final = (char)(Z_value_final /4); } //-----------主函数----------------------------------------------------------- void main(void) { OSC_Init(); Port_Init(); TimerA_UART_init(); MMA7660_Init(); __enable_interrupt(); TimerA_UART_print("All Initialization is OK!"); for (;;) { //__bis_SR_register(LPM0_bits); Read3axle(); if (X_value_final>0) P1OUT|= BIT0; else if(X_value_final<0) P1OUT&=~ BIT0; else _nop(); //------------------------------ TimerA_UART_print("X_value---->"); output((unsigned int )X_value,4); TimerA_UART_print(" "); //------------------------------ TimerA_UART_print("Y_value---->"); output((unsigned int )Y_value,4); TimerA_UART_print(" "); //------------------------------ TimerA_UART_print("Z_value---->"); output((unsigned int )Z_value,4); TimerA_UART_print(""); //------------------------------ P1OUT ^= BIT6 ; //delay_us(20000); } } //-------------------华丽的分割线----------------------------------------------------------------- //file2 : g2452uart.h #include "msp430g2452.h" //------------------------------------------------------------------------------ // Hardware-related definitions //------------------------------------------------------------------------------ #define UART_TXD 0x02 // TXD on P1.1 (Timer0_A.OUT0) #define UART_RXD 0x04 // RXD on P1.2 (Timer0_A.CCI1A) //------------------------------------------------------------------------------ // Conditions for 9600 Baud SW UART, SMCLK = 1MHz //------------------------------------------------------------------------------ #define UART_TBIT_DIV_2 (1000000 / (9600 * 2)) #define UART_TBIT (1000000 / 9600) //------------------------------------------------------------------------------ // Global variables used for full-duplex UART communication //------------------------------------------------------------------------------ unsigned int txData; // UART internal variable for TX unsigned char rxBuffer; // Received UART character //------------------------------------------------------------------------------ // 串口通信的接口函数说明： //------------------------------------------------------------------------------ void TimerA_UART_init(void); //TimerA_UART_init()模拟串口通信初始化函数,在main()函数中调用此函数就可以使用一下两个函数了 void TimerA_UART_tx(unsigned char byte); //TimerA_UART_tx( byte ) 通过串口发送一字节的数据 void TimerA_UART_print(char *string); //TimerA_UART_print(*string) 通过串口发送任意字节的字符穿 void output(unsigned int num , int n ); //输出一个数字 //注：接收的一字节数据存在rxBuffer变量里。 void Port1_Init() { P1OUT = 0x00; // Initialize all GPIO P1SEL = UART_TXD + UART_RXD; // Timer function for TXD/RXD pins // P1DIR = 0xFF & ~UART_RXD; // Set all pins but RXD to output //设置TXD为输出模式，P1.1和P1.2两个调试小灯也为输出模式。RXD为输入模式。 P1DIR |= UART_TXD+BIT0+BIT6; P1DIR &=~ UART_RXD; P1OUT &=~ BIT0+BIT6 ; //初始化让两个灯都灭。 } //------------------------------------------------------------------------------ // Function configures Timer_A for full-duplex UART operation //------------------------------------------------------------------------------ void TimerA_UART_init(void) { Port1_Init(); //P1端口初始化！ TACCTL0 = OUT; // Set TXD Idle as Mark = '1' TACCTL1 = SCS + CM1 + CAP + CCIE; // Sync, Neg Edge, Capture, Int TACTL = TASSEL_2 + MC_2; // SMCLK, start in continuous mode } //------------------------------------------------------------------------------ // Outputs one byte using the Timer_A UART //------------------------------------------------------------------------------ void TimerA_UART_tx(unsigned char byte) { while (TACCTL0 & CCIE); // Ensure last char got TX'd TACCR0 = TAR; // Current state of TA counter TACCR0 += UART_TBIT; // One bit time till first bit TACCTL0 = OUTMOD0 + CCIE; // Set TXD on EQU0, Int txData = byte; // Load global variable txData |= 0x100; // Add mark stop bit to TXData txData <<= 1; // Add space start bit } //------------------------------------------------------------------------------ // Prints a string over using the Timer_A UART //------------------------------------------------------------------------------ void TimerA_UART_print(char *string) { while (*string) { TimerA_UART_tx(*string++); } } void output(unsigned int num , int n ) { char *p,pd[4]; p=pd; pd[0]=num/1000 +48 ; //千位 pd[1]=num/100 +48 ;// 百位 pd[2]=num0/10 +48 ; //十位 pd[3]=num +48;//个位 while (n--) TimerA_UART_tx((*p++)); } //------------------------------------------------------------------------------ // Timer_A UART - Transmit Interrupt Handler //------------------------------------------------------------------------------ #pragma vector = TIMER0_A0_VECTOR __interrupt void Timer_A0_ISR(void) { static unsigned char txBitCnt = 10; TACCR0 += UART_TBIT; // Add Offset to CCRx if (txBitCnt == 0) { // All bits TXed? TACCTL0 &= ~CCIE; // All bits TXed, disable interrupt txBitCnt = 10; // Re-load bit counter } else { if (txData & 0x01) { TACCTL0 &= ~OUTMOD2; // TX Mark '1' } else { TACCTL0 |= OUTMOD2; // TX Space '0' } txData >>= 1; txBitCnt--; } } //------------------------------------------------------------------------------ // Timer_A UART - Receive Interrupt Handler //------------------------------------------------------------------------------ #pragma vector = TIMER0_A1_VECTOR __interrupt void Timer_A1_ISR(void) { static unsigned char rxBitCnt = 8; static unsigned char rxData = 0; switch (__even_in_range(TA0IV, TA0IV_TAIFG)) { // Use calculated branching case TA0IV_TACCR1: // TACCR1 CCIFG - UART RX TACCR1 += UART_TBIT; // Add Offset to CCRx if (TACCTL1 & CAP) { // Capture mode = start bit edge TACCTL1 &= ~CAP; // Switch capture to compare mode TACCR1 += UART_TBIT_DIV_2; // Point CCRx to middle of D0 } else { rxData >>= 1; if (TACCTL1 & SCCI) { // Get bit waiting in receive latch rxData |= 0x80; } rxBitCnt--; if (rxBitCnt == 0) { // All bits RXed? rxBuffer = rxData; // Store in global variable rxBitCnt = 8; // Re-load bit counter TACCTL1 |= CAP; // Switch compare to capture mode //__bic_SR_register_on_exit(LPM0_bits); // Clear LPM0 bits from 0(SR) } } break; } } //----------------------华丽的分割线2-------------------------------------------------------- //file :MMA7660FC.h #ifndef _MMA7660FC_H #define _MMA7660FC_H #define MMA7660FC_ADD 0x4C //Please contact the factory to request a different IIC address #define MMA7660FC_MW_ADD 0x98 //master write address #define MMA7660FC_MR_ADD 0x99 //master read address #define SlaveAddress 0x98 //从机地址 #define X_outAddr 0x00 #define Y_outAddr 0x01 #define Z_outAddr 0x02 // IIC Register Address #define MMA7660_XOUT 0x00 #define MMA7660_YOUT 0x01 #define MMA7660_ZOUT 0x02 #define MMA7660_TILT 0x03 #define MMA7660_SRST 0x04 #define MMA7660_SPCNT 0x05 #define MMA7660_INTSU 0x06 #define MMA7660_MODE 0x07 #define MMA7660_SR 0x08 #define MMA7660_PDET 0x09 #define MMA7660_PD 0x0A #endif ////////////////////////////////////////////////////////////////////////////////////////////////////\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ //以上为所有程序源码！编译工具CCS V5.0 复制代码
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