430单片机的UCSWRST是控制什么的啊

只看该作者 · 2011-12-5 14:59

P3SEL |= 0x06;                         // 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 = 14;                            // fSCL = SMCLK/12 = ~100kHz
UCB0BR1 = 0;
UCB0I2CSA = 0x00;                      // Slave Address is 048h
UCB0CTL1 &= ~UCSWRST;                   // Clear SW reset, resume operation

手册上说UCSWRST是软件复位，可是我看程序里面先复位，然后配置UCB0CTL0，然后又复位了，这怎么解释啊？