资 源 简 介
嵌入式系统由于本身存储容量的限制，急需扩展外存，多媒体卡（MMC）就是解决外存扩展的一个很好的方案。多媒体卡在多媒体领域广泛用作外部存储介质，但是大多数微处理器(MCU)并没有专门的多媒体卡控制器，多媒体卡的串行外设模式给了不具有多媒体卡控制器而需要读写多媒体卡的微处理器另一种选择，串行外设接口协议是广泛支持的总线协议,它通过串行外设接口总线与多媒体卡相连。本文介绍了MMC卡的工作原理和多媒体卡的串行外设接口协议(SPI)模式，给出了微处理器与MMC卡的接口电路、程序流程图及部分程序代码。
Abstract:
The embedded system is in dire need of expanding external memorizer due to its limited memory capacity, the mulTImedia card is the better one of the expanding memory. The mulTImedia card is widely used as external memory in mulTI-media applicaTIon,but most MCUs have no specialized multimedia controllers,the MCU with no specialized a multimedia controller has anther choice by using the SPI mode of the multimedia card, the SPI is a widely used bus protocol. It can be connected to the multimedia card with SPI bus. In this paper, the principle and the SPI mode of the multimedia card are introduced. The interface of the multimedia card and the microprocessor are given finally.
