Stellaris处理器的硬件设计参考

　　The information in this design guide is intended to be general enough to cover a wide range of designs bydescribing solutions for typical situations. However， because every system is different， it is inevitable thatthere will be conflicting requirements and potential trade-offs. This is especially true in designs that includehigh-performance analog circuits， radio frequencies， high voltages， or high currents. If your design includesthese features， then special considerations， beyond the scope of this application note， may be necessary.Where possible， the distinction is made between preferred practice and acceptable practice. This distinctionaddresses the reality that constraints such as size， cost， and layout restrictions might not always allow for

　　best-practice design.When considering which practices to apply to a design， one of the most important factors is the I/O switchingrate and current. If there is only low-speed， low-current switching on the Stellaris peripheral pins， thenacceptable-practice rules are likely sufficient. If high-speed switching is present， particularly with simultaneoustransitions （for example， the EPI module）， then best-practice rules are recommende