晶振的最大波特率及其误差介绍
用11.0592M和22.1184M，这样在通讯的时候误差最小。
Crystal(MHz) MaxBaudRate Error
1.000000 300 2.12%
1.843200 9600 0.00%
2.000000 300 0.79%
2.457600 300 0.78%
3.000000 1200 0.16%
3.579545 300 0.23%
3.686400 19200 0.00%
4.000000 1200 2.12%
4.194304 2400 1.14%
4.915200 1200 1.59%
5.000000 2400 1.36%
5.068800 2400 0.00%
6.000000 2400 0.16%
6.144000 1200 1.23%
7.372800 38400 0.00%
8.000000 2400 2.12%
10.000000 4800 1.36%
10.738635 2400 1.32%
11.000000 57600 0.54%
11.059200 57600 0.00%
12.000000 4800 0.16%
12.288000 2400 1.23%
14.318180 2400 0.23%
14.745600 38400 0.00%
15.000000 38400 1.73%
16.000000 4800 2.12%
18.432000 19200 0.00%
20.000000 9600 1.36%
22.118400 115200 0.00%
24.000000 9600 0.16%
24.576000 4800 1.23%
25.000000 4800 0.47%
28.000000 9600 1.27%
32.000000 9600 2.12%
