TI中文支持网#include <msp430.h>
unsigned int RxByteCtr;
unsigned int RxWord;
int main(void)
{
WDTCTL = WDTPW + WDTHOLD; // Stop WDT
P1DIR |= BIT0; // P1.0 output
P1SEL |= BIT6 + BIT7; // Assign I2C pins to USCI_B0
P1SEL2|= BIT6 + BIT7; // Assign I2C pins to USCI_B0
UCB0CTL1 |= UCSWRST; // Enable SW reset
UCB0CTL0 = UCMST + UCMODE_3 + UCSYNC; // I2C Master, synchronous mode
UCB0CTL1 = UCSSEL_2 + UCSWRST; // Use SMCLK, keep SW reset
UCB0BR0 = 12; // fSCL = SMCLK/12 = ~100kHz
UCB0BR1 = 0;
UCB0I2CSA = 0x4e; // Set slave address
UCB0CTL1 &= ~UCSWRST; // Clear SW reset, resume operation
IE2 |= UCB0RXIE; // Enable RX interrupt
TACTL = TASSEL_2 + MC_2; // SMCLK, contmode
while (1)
{
RxByteCtr = 2; // Load RX byte counter
UCB0CTL1 |= UCTXSTT; // I2C start condition
__bis_SR_register(CPUOFF + GIE); // Enter LPM0, enable interrupts
// Remain in LPM0 until all data
// is RX'd
if (RxWord < 0x1d00) // >28C?
P1OUT &= ~0x01; // No, P1.0 = 0
else
P1OUT |= 0x01; // Yes, P1.0 = 1
__disable_interrupt();
TACCTL0 |= CCIE; // TACCR0 interrupt enabled
__bis_SR_register(CPUOFF + GIE); // Enter LPM0, enable interrupts
// Remain in LPM0 until TACCR0
// interrupt occurs
TACCTL0 &= ~CCIE; // TACCR0 interrupt disabled
}
}
#pragma vector = TIMER0_A0_VECTOR
__interrupt void TA0_ISR(void)
{
__bic_SR_register_on_exit(CPUOFF); // Exit LPM0
}
// The USCIAB0TX_ISR is structured such that it can be used to receive any
// 2+ number of bytes by pre-loading RxByteCtr with the byte count.
#pragma vector = USCIAB0TX_VECTOR
__interrupt void USCIAB0TX_ISR(void)
{
RxByteCtr–; // Decrement RX byte counter
if (RxByteCtr)
{
RxWord = (unsigned int)UCB0RXBUF << 8; // Get received byte
if (RxByteCtr == 1) // Only one byte left?
UCB0CTL1 |= UCTXSTP; // Generate I2C stop condition
}
else
{
RxWord |= UCB0RXBUF; // Get final received byte,
// Combine MSB and LSB
__bic_SR_register_on_exit(CPUOFF); // Exit LPM0
}
}
Maka Luo：
这个是官方例程吗？
个人觉得逻辑上有错误，标注在你的代码中。
不妨在你中断函数设置断点，看看程序运行是否如我的推测。谢谢！
yao wang5
#include <msp430.h>
unsigned int RxByteCtr;unsigned int RxWord;
int main(void){WDTCTL = WDTPW + WDTHOLD; // Stop WDTP1DIR |= BIT0; // P1.0 outputP1SEL |= BIT6 + BIT7; // Assign I2C pins to USCI_B0P1SEL2|= BIT6 + BIT7; // Assign I2C pins to USCI_B0UCB0CTL1 |= UCSWRST; // Enable SW resetUCB0CTL0 = UCMST + UCMODE_3 + UCSYNC; // I2C Master, synchronous modeUCB0CTL1 = UCSSEL_2 + UCSWRST; // Use SMCLK, keep SW resetUCB0BR0 = 12; // fSCL = SMCLK/12 = ~100kHzUCB0BR1 = 0;UCB0I2CSA = 0x4e; // Set slave addressUCB0CTL1 &= ~UCSWRST; // Clear SW reset, resume operationIE2 |= UCB0RXIE; // Enable RX interruptTACTL = TASSEL_2 + MC_2; // SMCLK, contmode
while (1){RxByteCtr = 2; // Load RX byte counter //每次运行到这里，这个变量都强行赋值为2 UCB0CTL1 |= UCTXSTT; // I2C start condition__bis_SR_register(CPUOFF + GIE); // Enter LPM0, enable interrupts
// 如果I2C接收到数据中断，其值应该只获取到1byte 程序继续往下运行。 你可以发现你获取的值应该就是一个BYTE 后又回到RxByteCtr = 2;这个代码
// Remain in LPM0 until all data// is RX'd
if (RxWord < 0x1d00) // >28C?P1OUT &= ~0x01; // No, P1.0 = 0elseP1OUT |= 0x01; // Yes, P1.0 = 1
__disable_interrupt(); // 这个可以屏蔽 TACCTL0 |= CCIE; // TACCR0 interrupt enabled //这个定时还有其它配置没有__bis_SR_register(CPUOFF + GIE); // Enter LPM0, enable interrupts// Remain in LPM0 until TACCR0// interrupt occursTACCTL0 &= ~CCIE; // TACCR0 interrupt disabled}}
#pragma vector = TIMER0_A0_VECTOR__interrupt void TA0_ISR(void){__bic_SR_register_on_exit(CPUOFF); // Exit LPM0}
// The USCIAB0TX_ISR is structured such that it can be used to receive any// 2+ number of bytes by pre-loading RxByteCtr with the byte count.#pragma vector = USCIAB0TX_VECTOR__interrupt void USCIAB0TX_ISR(void){RxByteCtr–; // Decrement RX byte counter
if (RxByteCtr){RxWord = (unsigned int)UCB0RXBUF << 8; // Get received byteif (RxByteCtr == 1) // Only one byte left?UCB0CTL1 |= UCTXSTP; // Generate I2C stop condition}else{RxWord |= UCB0RXBUF; // Get final received byte,// Combine MSB and LSB__bic_SR_register_on_exit(CPUOFF); // Exit LPM0}}
yao wang5：
回复 Maka Luo:
现在按你说的操作，早中断函数设置断点，波形和寄存器都是对的，请问，程序该怎么改呢？谢谢
yao wang5：
回复 Maka Luo:
刚才设了断点运行正常，同样的程序，现在设置断点，程序不停止，也没有波形输出，是什么原因？ccs编译器的问题么？
Maka Luo：
改成这样测试一下，看看结果是否正确。Timer 配置不完整，你可以在这里换成一个比较长的延时看看，这个是等待I2C数据接收完成。
yao wang5
#include <msp430.h>
unsigned int RxByteCtr;unsigned int RxWord;
int main(void){WDTCTL = WDTPW + WDTHOLD; // Stop WDTP1DIR |= BIT0; // P1.0 outputP1SEL |= BIT6 + BIT7; // Assign I2C pins to USCI_B0P1SEL2|= BIT6 + BIT7; // Assign I2C pins to USCI_B0UCB0CTL1 |= UCSWRST; // Enable SW resetUCB0CTL0 = UCMST + UCMODE_3 + UCSYNC; // I2C Master, synchronous modeUCB0CTL1 = UCSSEL_2 + UCSWRST; // Use SMCLK, keep SW resetUCB0BR0 = 12; // fSCL = SMCLK/12 = ~100kHzUCB0BR1 = 0;UCB0I2CSA = 0x4e; // Set slave addressUCB0CTL1 &= ~UCSWRST; // Clear SW reset, resume operation
RxByteCtr = 2; // Load RX byte counter
IE2 |= UCB0RXIE; // Enable RX interruptTACTL = TASSEL_2 + MC_2; // SMCLK, contmode
while (1){//RxByteCtr = 2; // Load RX byte counterUCB0CTL1 |= UCTXSTT; // I2C start condition//__bis_SR_register(CPUOFF + GIE); // Enter LPM0, enable interrupts// Remain in LPM0 until all data// is RX'd
if (RxWord < 0x1d00) // >28C?P1OUT &= ~0x01; // No, P1.0 = 0elseP1OUT |= 0x01; // Yes, P1.0 = 1
//__disable_interrupt();TACCTL0 |= CCIE; // TACCR0 interrupt enabled__bis_SR_register(CPUOFF + GIE); // Enter LPM0, enable interrupts// Remain in LPM0 until TACCR0// interrupt occursTACCTL0 &= ~CCIE; // TACCR0 interrupt disabled}}
#pragma vector = TIMER0_A0_VECTOR__interrupt void TA0_ISR(void){__bic_SR_register_on_exit(CPUOFF); // Exit LPM0}
// The USCIAB0TX_ISR is structured such that it can be used to receive any// 2+ number of bytes by pre-loading RxByteCtr with the byte count.#pragma vector = USCIAB0TX_VECTOR__interrupt void USCIAB0TX_ISR(void){RxByteCtr–; // Decrement RX byte counter
if (RxByteCtr){RxWord = (unsigned int)UCB0RXBUF << 8; // Get received byteif (RxByteCtr == 1) // Only one byte left?UCB0CTL1 |= UCTXSTP; // Generate I2C stop condition}else{RxWord |= UCB0RXBUF; // Get final received byte,// Combine MSB and LSB__bic_SR_register_on_exit(CPUOFF); // Exit LPM0
RxByteCtr = 2; // Load RX byte counter}}
yao wang5：
回复 Maka Luo:
这个出了波形，凡是波形不正确，寄存器里的值还是0x80。用刚才测试的程序，没有波形了并且scl被拉低了，是这颗芯片msp430g2533的iic存在问题么？时好时坏？有没有这颗芯片不用中断的iic的例程呢？
Maka Luo：
回复 yao wang5:
在MSPWARE中有很多I2C例程，建议你还是跑一下例程先。如上图所示，CCS环境中。
Maka Luo：
回复 yao wang5:
你贴的好像是TI给官方例程，我刚刚检查一下逻辑，是没有问题的。如果波形出不来是因为进入低功耗的原因吗？
那我建议如下更改：
#include <msp430.h>
unsigned int RxByteCtr;unsigned int RxWord;
int main(void){ WDTCTL = WDTPW + WDTHOLD; // Stop WDT P1DIR |= BIT0; // P1.0 output P1SEL |= BIT6 + BIT7; // Assign I2C pins to USCI_B0 P1SEL2|= BIT6 + BIT7; // Assign I2C pins to USCI_B0 UCB0CTL1 |= UCSWRST; // Enable SW reset UCB0CTL0 = UCMST + UCMODE_3 + UCSYNC; // I2C Master, synchronous mode UCB0CTL1 = UCSSEL_2 + UCSWRST; // Use SMCLK, keep SW reset UCB0BR0 = 12; // fSCL = SMCLK/12 = ~100kHz UCB0BR1 = 0; UCB0I2CSA = 0x4e; // Set slave address UCB0CTL1 &= ~UCSWRST; // Clear SW reset, resume operation IE2 |= UCB0RXIE; // Enable RX interrupt TACTL = TASSEL_2 + MC_2; // SMCLK, contmode
while (1) { RxByteCtr = 2; // Load RX byte counter UCB0CTL1 |= UCTXSTT; // I2C start condition//__bis_SR_register(CPUOFF + GIE); // Enter LPM0, enable interrupts//不进入低功耗状态 // Remain in LPM0 until all data // is RX'd
while(RxByteCtr); //等待数据接收完毕 两个字节
if (RxWord < 0x1d00) // >28C? P1OUT &= ~0x01; // No, P1.0 = 0 else P1OUT |= 0x01; // Yes, P1.0 = 1
__disable_interrupt(); TACCTL0 |= CCIE; // TACCR0 interrupt enabled __bis_SR_register(CPUOFF + GIE); // Enter LPM0, enable interrupts // Remain in LPM0 until TACCR0 // interrupt occurs TACCTL0 &= ~CCIE; // TACCR0 interrupt disabled }}
#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)#pragma vector = TIMER0_A0_VECTOR__interrupt void TA0_ISR(void)#elif defined(__GNUC__)void __attribute__ ((interrupt(TIMER0_A0_VECTOR))) TA0_ISR (void)#else#error Compiler not supported!#endif{ __bic_SR_register_on_exit(CPUOFF); // Exit LPM0}
// The USCIAB0TX_ISR is structured such that it can be used to receive any// 2+ number of bytes by pre-loading RxByteCtr with the byte count.#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)#pragma vector = USCIAB0TX_VECTOR__interrupt void USCIAB0TX_ISR(void)#elif defined(__GNUC__)void __attribute__ ((interrupt(USCIAB0TX_VECTOR))) USCIAB0TX_ISR (void)#else#error Compiler not supported!#endif{ RxByteCtr–; // Decrement RX byte counter
if (RxByteCtr) { RxWord = (unsigned int)UCB0RXBUF << 8; // Get received byte if (RxByteCtr == 1) // Only one byte left? UCB0CTL1 |= UCTXSTP; // Generate I2C stop condition } else { RxWord |= UCB0RXBUF; // Get final received byte, // Combine MSB and LSB//__bic_SR_register_on_exit(CPUOFF); // Exit LPM0 }}
yao wang5：
回复 Maka Luo:
都还是老样子，没有波形，寄存器里的数值也不变，是不是芯片的iic硬件有问题？能不能提供一下用IO口模拟iic读取tmp101温度的例程，来测试下p1.6和p1.7是不是正常，谢谢
Maka Luo：
回复 yao wang5:
在中断函数中设置断点试试？程序运行停在什么地方？可以把后面定时器进入LPM0也屏蔽看看。
yao wang5：
回复 Maka Luo:
设置了断点程序不停，每次手动暂停程序都停在这里while(RxByteCtr); //等待数据接收完毕 两个字节
还是没有波形
