使用定时器一CCR0硬件输出模式和SCCI数据锁

实现UART函数@ 2400波特。软件不能直接读取和

写信给RX和TX别针,相反正确使用输出模式和SCCI数据锁了。使用这些硬件特性消除了ISR

延迟效应作为硬件确保输出和输入位自锁和时机是完美的同步与定时器一个不管其他软件活动。

-Use Timer_A CCR0 hardware output modes and SCCI data latch

to implement UART function @ 2400 baud. Software does not directly read and

　write to RX and TX pins, instead proper use of output modes and SCCI data latch are demonstrated. Use of these hardware features eliminates ISR

latency effects as hardware insures that output and input bit latching and　timing are perfectly synchronised with Timer_A regardless of other software activity.