第一次在eeworld发帖求助，请前辈指教！提问题排版有什么问题我会改的！！
背景：
用MSP430f5529和时钟模块DS1307进行硬件i2c通讯。用Ti自带的例程“Master multiple bytes to Slave”进行修改（增加了时钟初始化USC_init、读模式read_mode,写模式write_mode）。
程序的流程大概是：初始化时钟、i2c，写第一组数据0x03和0x05并结束，写第二组数据0x04和0x06并restart再写0x04和0x06，结束。
目的是为了弄清楚restart的使用。
先放逻辑分析仪时序：
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问题：
1. 在写第一组数据（0x03，0x05）时序正确的前提下，写第二组数据（0x04，0x06）后进行restart，能看到restart条件产生（第三个绿点），也传输了slave address和读写位（restart条件后的0xD0），但是后续的scl和sda就没有变化了，请问这是哪里出了问题？
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2. （可能与问题1相关）进行单步调试，在运行到
- UCB0CTL1 |= UCTXSTT; //restart，全代码第 53 行
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这一步的时候，按照user's guide中的说法，将UCTXSTT置位后，如果从机对起始信号有响应，将会把UCB0TXIFG置位。但是调试时没有置位，导致没有进入中断，请问哪里可能出现了问题？
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3. 如代码
- UCB0CTL1 |= UCTXSTT;
- __bis_SR_register(LPM0_bits); //LPM0
- __no_operation();
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中，产生起始条件后总要直接进入低功耗模式。再如Tx中断里，代码
- UCB0CTL1 |= UCTXSTP; // I2C stop condition
- UCB0IFG &= ~UCTXIFG; // Clear USCI_B0 TX int flag
- __bic_SR_register_on_exit(LPM0_bits); // Exit LPM0
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中，产生终止条件后总要退出中断时退出低功耗模式。请问这是如何对通讯产生影响的，应当在何时进入或退出低功耗模式。
下面附全代码：
- #include
- #define SMCLK_FREQ 24000000
- #define I2C_FREQ 100000
- void USC_init(void); //clock initialize
- void initi2c(void); //i2c initialize
- void read_mode(void); //read mode setting
- void write_mode(void); //write mode setting
- unsigned char *PTxData; // pointer to TX data
- unsigned char TXByteCtr; //number of data to transmit
- unsigned char TxData[] = // table of data to transmit
- {
- 0x03,
- 0x05
- };
- int flag; //restart flag
- int main(void)
- {
- unsigned int i;
- WDTCTL = WDTPW + WDTHOLD; // Stop WDT
- USC_init();
- initi2c();
- write_mode(); //write
- PTxData = (unsigned char *)TxData;
- TXByteCtr = sizeof TxData;
- flag = 0; //no restart
- UCB0CTL1 |= UCTXSTT;
- __bis_SR_register(LPM0_bits); //LPM0
- __no_operation();
- while (UCB0CTL1 & UCTXSTP);
- for(i=0;i<10;i++); // Delay required between transaction
- TxData[0]++; //change the TxData
- TxData[1]++;
- write_mode();
- PTxData = (unsigned char *)TxData;
- TXByteCtr = sizeof TxData;
- flag = 1; //restart required
- UCB0CTL1 |= UCTXSTT;
- __bis_SR_register(LPM0_bits); //LPM0
- __no_operation();
- write_mode(); //transmit data again
- PTxData = (unsigned char *)TxData;
- TXByteCtr = sizeof TxData;
- flag = 0;
- UCB0CTL1 |= UCTXSTT; //restart
- __bis_SR_register(LPM0_bits); //LPM0
- __no_operation();
- while (UCB0CTL1 & UCTXSTP);
- while(1); //finish
- }
- #pragma vector = USCI_B0_VECTOR
- __interrupt void USCI_B0_ISR(void)
- {
- switch(__even_in_range(UCB0IV,12))
- {
- case 0: break; // Vector 0: No interrupts
- case 2: break; // Vector 2: ALIFG
- case 4: break; // Vector 4: NACKIFG
- case 6: break; // Vector 6: STTIFG
- case 8: break; // Vector 8: STPIFG
- case 10: break; // Vector 10: RXIFG
- case 12: // Vector 12: TXIFG
- if (TXByteCtr) // Check TX byte counter
- {
- UCB0TXBUF = *PTxData++; // Load TX buffer
- TXByteCtr--; // Decrement TX byte counter
- }
- else
- {
- if (!flag)
- {
- UCB0CTL1 |= UCTXSTP; // I2C stop condition
- UCB0IFG &= ~UCTXIFG; // Clear USCI_B0 TX int flag
- __bic_SR_register_on_exit(LPM0_bits); // Exit LPM0
- }
- else
- {
- //UCB0IFG &= ~UCTXIFG; // Clear USCI_B0 TX int flag
- __bic_SR_register_on_exit(LPM0_bits); // Exit LPM0
- }
- }
- default: break;
- }
- }
- void USC_init()
- {
- P5SEL |= BIT4+BIT5;
- UCSCTL6 &= ~(XT1OFF);
- UCSCTL6 |= XCAP_3;
- UCSCTL4 |= SELA_0+SELS_3;
- UCSCTL0 = 0x0000;
- do
- {
- UCSCTL7 &= ~XT1LFOFFG;
- }while (UCSCTL7 & XT1LFOFFG);
- __bis_SR_register(SCG0);
- UCSCTL1 = DCORSEL_5;
- UCSCTL2 = FLLD_1 + 366;
- __bic_SR_register(SCG0);
- __delay_cycles(750000);
- }
- void initi2c()
- {
- USC_init();
- P3SEL |= 0x03; // 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 = (SMCLK_FREQ/I2C_FREQ);
- UCB0BR1 = ((SMCLK_FREQ/I2C_FREQ)>>8) & 0xFF;
- UCB0I2CSA = (0xD0 >> 1); // Slave Address is 048h
- UCB0CTL1 &= ~UCSWRST; // Clear SW reset, resume operation
- __bis_SR_register(GIE);
- }
- void read_mode(void)
- {
- UCB0CTL1 &= ~UCTR;
- UCB0IE |= UCRXIE;
- UCB0IE &= ~UCTXIE;
- }
- void write_mode(void)
- {
- UCB0CTL1 |= UCTR;
- UCB0IE &= ~UCRXIE;
- UCB0IE |= UCTXIE;
- }
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排版不好。。。
请各位前辈指教！！
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