SL-MEGA8开发板实验，自引导IAP实验。
注意：
　1、使用外部晶振、实时时钟晶振时，数码管的DP、G段和PB7、PB6的连接应该断开，
　　 而使用内部RC振荡时，数码管的DP、G段和PB7、PB6的连接可以连接。
　2、使用外部时钟，数码管的G段和PB6的连接应该断开。,SL-MEGA8 development board experiment, since the IAP to guide experiments. Note: 1, the use of an external crystal oscillator, real-time clock crystal oscillator, the digital control of the DP, G, and PB7, PB6 connection should be disconnected, and the use of the internal RC oscillation, the digital control of DP, G, and PB7, PB6 connection can be connected. 2, the use of an external clock, digital tube, and the G of the connection should be disconnected PB6.