使用您的MCU的內(nèi)存架構(gòu)，提高應(yīng)用效率

　　現(xiàn)代微控制器具有多種記憶元素，并了解他們的組織、性能的限制和功率的影響可能是實(shí)現(xiàn)一個(gè)高效應(yīng)用的關(guān)鍵。特別是，用于代碼存儲(chǔ)的片上閃存的特性，用于數(shù)據(jù)存儲(chǔ)的片上SRAM的組織和片外存儲(chǔ)器的訪問(wèn)特性將有顯著影響整體處理效率。讓我們檢查這些關(guān)鍵的內(nèi)存元素，以更好地了解如何最有效地使用它們，以最大限度地提高性能，降低功耗和優(yōu)化系統(tǒng)成本。

　　片上閃存

　　片上閃存可能是任何應(yīng)用程序中最關(guān)鍵的存儲(chǔ)元件，因?yàn)樗ǔＪ翘幚砥鞯乃兄噶畹膩?lái)源。如果指令不能有效地獲取，則您的整體MCU性能將受到影響。向CPU傳遞指令有兩種不同的方法。在一種方法中，內(nèi)存運(yùn)行速度快，需要匹配的指令周期的CPU。瑞薩RX600組，例如，采用先進(jìn)的Flash技術(shù)，提供高性能的零等待狀態(tài)訪問(wèn)指令存儲(chǔ)器。這種方法導(dǎo)致簡(jiǎn)化的CPU架構(gòu)和確定的時(shí)序。

　　Access to Flash memory typically uses a two-port approach with CPU access， via a high-speed bus for read operations and slower access， using a Flash memory controller for write operations. The Flash memory interface for the RX600 is illustrated in Figure 1. Note that the Flash memory is further segmented into a data Flash section， for storing non-volatile information that is frequently modified， and the instruction section， which is typically considered as Read-Only Memory （ROM）， even though it uses Flash technology and can be reprogrammed many times by the user during manufacturing or via system updates. The Flash Control Unit （FCU） is a standalone specialized processor that managed Flash writes and has its own RAM and firmware memory blocks. The CPU can initiate FCU operations; this is accomplished using the peripheral bus shown at the top of Figure 1.