硬件IIC 只发送器件地址，不发送数据

lovin

用的是官方的代码
出来的波形，是把 只与slave address 有关(定义的是0x48，发0x90, 定义0x01，发0x02，定义0x00,发0x00)发送出来，并且不发送数据
是不是只要收不到ACK ，它就只发送

[mw_shl_code=c,true]#include <msp430.h> unsigned char TXData; unsigned char TXByteCtr; int main(void) { WDTCTL = WDTPW + WDTHOLD; // Stop WDT 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 = 12; // fSCL = SMCLK/12 = ~100kHz UCB0BR1 = 0; UCB0I2CSA = 0x48; // Slave Address is 048h UCB0CTL1 &= ~UCSWRST; // Clear SW reset, resume operation UCB0IE |= UCTXIE; // Enable TX interrupt TXData = 0x01; // Holds TX data while (1) { TXByteCtr = 1; // Load TX byte counter while (UCB0CTL1 & UCTXSTP); // Ensure stop condition got sent UCB0CTL1 |= UCTR + UCTXSTT; // I2C TX, start condition __bis_SR_register(LPM0_bits + GIE); // Enter LPM0 w/ interrupts __no_operation(); // Remain in LPM0 until all data // is TX'd TXData++; // Increment data byte } } //------------------------------------------------------------------------------ // The USCIAB0_ISR is structured such that it can be used to transmit any // number of bytes by pre-loading TXByteCtr with the byte count. //------------------------------------------------------------------------------ #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 = TXData; // Load TX buffer TXByteCtr--; // Decrement TX byte counter } else { UCB0CTL1 |= UCTXSTP; // I2C stop condition UCB0IFG &= ~UCTXIFG; // Clear USCI_B0 TX int flag __bic_SR_register_on_exit(LPM0_bits); // Exit LPM0 } break; default: break; } }[/mw_shl_code]

正点原子

帮顶。。。。。