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嵌(qian)入(ru)式系(xi)(xi)(xi)(xi)統(tong)由硬(ying)件(jian)(jian)(jian)環境(jing)、嵌(qian)入(ru)式操(cao)(cao)作系(xi)(xi)(xi)(xi)統(tong)和應用(yong)(yong)程序組成，硬(ying)件(jian)(jian)(jian)環境(jing)是操(cao)(cao)作系(xi)(xi)(xi)(xi)統(tong)和應用(yong)(yong)程序運(yun)(yun)行(xing)的(de)(de)硬(ying)件(jian)(jian)(jian)平臺(tai)，它(ta)隨應用(yong)(yong)的(de)(de)不同而有(you)(you)不同的(de)(de)要求。硬(ying)件(jian)(jian)(jian)平臺(tai)的(de)(de)多(duo)樣性是嵌(qian)入(ru)式系(xi)(xi)(xi)(xi)統(tong)的(de)(de)主要特(te)點，如何使嵌(qian)入(ru)式操(cao)(cao)作系(xi)(xi)(xi)(xi)統(tong)在(zai)不同的(de)(de)硬(ying)件(jian)(jian)(jian)平臺(tai)上有(you)(you)效地運(yun)(yun)行(xing)，是嵌(qian)入(ru)式系(xi)(xi)(xi)(xi)統(tong)開發中(zhong)需(xu)要解(jie)決的(de)(de)關鍵問題。解(jie)決的(de)(de)方法是在(zai)硬(ying)件(jian)(jian)(jian)平臺(tai)和操(cao)(cao)作系(xi)(xi)(xi)(xi)統(tong)之間提供硬(ying)件(jian)(jian)(jian)相關層(ceng)來屏蔽這(zhe)些硬(ying)件(jian)(jian)(jian)的(de)(de)差(cha)異，給操(cao)(cao)作系(xi)(xi)(xi)(xi)統(tong)提供統(tong)一的(de)(de)運(yun)(yun)行(xing)環境(jing)，這(zhe)種(zhong)硬(ying)件(jian)(jian)(jian)相關層(ceng)就(jiu)是嵌(qian)入(ru)式系(xi)(xi)(xi)(xi)統(tong)中(zhong)的(de)(de)板級支持包BSP(Board Support Package，簡稱(cheng)BSP)。

BSP是(shi)嵌(qian)入式系(xi)統中介于(yu)硬(ying)件(jian)(jian)平臺和操(cao)作(zuo)系(xi)統之間(jian)的(de)(de)(de)中間(jian)層軟件(jian)(jian)，主要目的(de)(de)(de)是(shi)為了屏蔽底層硬(ying)件(jian)(jian)的(de)(de)(de)多樣性(xing)，根據(ju)操(cao)作(zuo)系(xi)統的(de)(de)(de)要求完成對硬(ying)件(jian)(jian)的(de)(de)(de)直接操(cao)作(zuo)，向操(cao)作(zuo)系(xi)統提供(gong)底層硬(ying)件(jian)(jian)信息并終啟(qi)動操(cao)作(zuo)系(xi)統。BSP具(ju)有硬(ying)件(jian)(jian)相(xiang)關性(xing)和操(cao)作(zuo)系(xi)統相(xiang)關性(xing)的(de)(de)(de)特點，其(qi)主要作(zuo)用(yong)包(bao)括：

(1)初始化底層硬件，為操作系統提供底層硬件信息；
        (2)初始化相關硬件設備，主要是存儲設備、通信設備；
        (3)檢測系統硬件是否正常；
         (4)加載操作系統并啟(qi)動系統運行。

BSP是相對(dui)于操作(zuo)系(xi)(xi)統(tong)(tong)而言的(de)，不(bu)(bu)同(tong)(tong)的(de)操作(zuo)系(xi)(xi)統(tong)(tong)有(you)不(bu)(bu)同(tong)(tong)定義(yi)形(xing)式的(de)BSP，要(yao)(yao)(yao)(yao)求(qiu)BSP所(suo)實(shi)現的(de)功(gong)能(neng)也有(you)所(suo)不(bu)(bu)同(tong)(tong)。在嵌入式Linux系(xi)(xi)統(tong)(tong)中，主(zhu)要(yao)(yao)(yao)(yao)是初始(shi)化(hua)底層硬(ying)(ying)件并(bing)引(yin)導操作(zuo)系(xi)(xi)統(tong)(tong)；同(tong)(tong)時，BSP又是和硬(ying)(ying)件相關(guan)的(de)，還要(yao)(yao)(yao)(yao)考(kao)慮對(dui)硬(ying)(ying)件的(de)初始(shi)化(hua)操作(zuo)。這(zhe)些初始(shi)化(hua)操作(zuo)主(zhu)要(yao)(yao)(yao)(yao)是對(dui)CPU、內存、中斷等相關(guan)的(de)寄存器(qi)及協處理器(qi)進行正(zheng)確(que)的(de)配置。在不(bu)(bu)同(tong)(tong)的(de)開發階(jie)段(duan)(duan)，因為(wei)核(he)心和文件系(xi)(xi)統(tong)(tong)所(suo)處的(de)位置不(bu)(bu)同(tong)(tong)，BSP所(suo)要(yao)(yao)(yao)(yao)完成的(de)工(gong)作(zuo)也有(you)所(suo)不(bu)(bu)同(tong)(tong)：在開發調試階(jie)段(duan)(duan)，BSP要(yao)(yao)(yao)(yao)能(neng)夠(gou)(gou)與主(zhu)機通信(xin)并(bing)從(cong)主(zhu)機下載核(he)心；在目標產(chan)品中，BSP要(yao)(yao)(yao)(yao)能(neng)夠(gou)(gou)從(cong)非易失存儲(chu)設備中加(jia)載核(he)心。