MCU與新的和不同的存儲單元和存儲器結(jié)構

　　記憶技術不停滯不前。存儲器結(jié)構的變化速度更快和更有效的結(jié)構的創(chuàng)建和使用在連續(xù)幾代人如DRAM SDRAM DDR DDR1、2、3、等。

　　然而，記憶的進化不僅限于結(jié)構的改進。存儲單元本身的基本技術已經(jīng)得到改善。專業(yè)的工藝和設計優(yōu)化低功耗，非易失性存儲，安全，或其他特殊需要。

　　本文著眼于嵌入式MCU的功能，不同類型的存儲器單元和存儲器結(jié)構。一些制造商提供這些MCU和索賠的優(yōu)點的競爭部分與常規(guī)內(nèi)存和體系結(jié)構。本文將研究幾種可供設計者選擇的方法。

　　In search of the perfect cell

　　Van Neumann， Harvard， and RISC architectures all use nonvolatile memory like EPROM and Flash for boot code and firmware. Most boot code is on chip， but ROMless parts also exist and will still use external OTP EPROM or Flash. Both of these technologies provide dense， fairly low-power， low-cost field- and factory-programmable solutions to a microcontroller’s firmware needs.

　　While legacy EPROM has over decades given way to Flash as the dominant storage technology， the quest has been to eliminate the barrier between volatility and rewriteability. Ultimately， everyone is seeking a single high-speed， nonvolatile， low-power， rewriteable， high-endurance cell that could be used everywhere.