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在做嵌入式硬件设计中,这几点需要关注

FABUSHIJIAN:2017-09-22   YUEDU:82CI


QIANRUSHISHEJISHIGEPANGDADEGONGCHENG,JINTIANJIUSHUOSHUOYINGJIANDIANLUSHEJIFANGMIANDEJIGEZHUYISHIXIANG,SHOUXIAN,ZANMENLEJIEXIAQIANRUSHIDEYINGJIANGOUJIA。

我们知道,CPU是这个系统的灵魂,所有的外围配置都与其相关联,这也突出了嵌入式设计的一个特点硬件可剪裁。在做嵌入式硬件设计中,以下几点需要关注。

第一、电源确定

DIANYUANDUIYUQIANRUSHIXITONGZHONGDEZUOYONGKEYIKANZUOSHIKONGQIDUIRENTIDEZUOYONG,SHENZHIGENGZHONGYAO:RENHUXIDEKONGQIZHONGYOUYANGQI、ERYANGHUATANHEDANQIDENGDANSHIHANLIANGWENDING,ZHEIJIUXIANGDANGYUDIANYUANXITONGZHONGGEZHONGZABO,WOMENXIWANGDEDAOCHUNJINGHEWENDINGFUHEYAOQIUDEDIANYUAN,DANYOUYUGEZHONGYINSUZHIYUE,ZHISHIWOMENDEMENGXIANG。ZHEIGEYAOGUANZHULIANGGEFANGMIAN:

a、电压

QIANRUSHIXITONGXUYAOGEZHONGLIANGJIDEDIANYUANBIRUCHANGJIANDE5v、3.3v、1.8vDENG,WEIJINLIANGJIANXIAODIANYUANDEWENBO,ZAIQIANRUSHIXITONGZHONGSHIYONGLDOQIJIAN。RUGUOCAIYONGDCDCBUJINGETOUDA,QIWENBOYESHIYIGEHENTOUTENGDEWENTI。

b、电流

QIANRUSHIXITONGDEZHENGCHANGYUNXINGBUDANXUYAOWENDINGZUGOUDEDIANYUAN,HAIYAOYOUZUGOUDEDIANLIU,YINCIZAIXUANZEDIANYUANQIJIANDESHIHOUXUYAOKAOLVQIFUZAI,WOSHEJISHIYIBANLIUYOU30%DEYULIANG。

如果是多层板,电源部分在layout的时候需电源分割,这时需要注意分割路径,尽量将一定量的电源放置在一起。如果是双面板,则走线宽度需要注意,在板子允许的情况下尽量加宽。合适的退耦电容尽量靠近电源管脚。

第二、 晶振确定

JINGZHENXIANGDANGYUQIANRUSHIXITONGDEXINZANG,QIWENDINGYUFOUZHIJIEGUANXIQIYUNXINGZHUANGTAIHETONGXUNXINGNENG。CHANGJIANDEZHENYOUWUYUANJINGZHEN,YOUYUANJINGZHEN,SHOUXIANYAOQUEDINGQIZHENDANGPINLV,QICIYAOQUEDINGJINGZHENLEIXING。

a、无源晶振

QIPIPEIDIANRONGHEPIPEIDIANZUDEXUANZE,ZHEIBUFENYIBANYIJUCANKAOSHOUCE。ZAIDANPIANJISHEJIZHONG,JINGCHANGSHIYONGCHAJIANJINGZHENPEIHECIPIANDIANRONG。ZAIARMZHONG,WEILEJIANSHAOKONGJIANHEBIANYUBUXIAN,JINGCHANGSHIYONGSIJIAOWUYUANJINGZHENPEIHETIEPIANDIANRONG。SUIRANWOMENDUIYUGUDINGJINGZHENDEPIPEIDIANLUBIJIAOSHUXI,DANSHIWEILEDADAOWANWUYISHI,HAISHIYAOKANCANKAOSHOUCEQUEDINGDIANRONGDAXIAO,SHIFOUXUYAOPIPEIDIANZUDENGXIJIE。

b、有源晶振

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在做电路板设计时需要注意晶振走线尽量靠近芯片,关键信号远离时钟走线。在条件允许的情况下增加接地保护环。如果是多层板,也要讲关键信号远离晶振的走线。

第三、 预留测试IO口

ZAIQIANRUSHIDIAOSHIJIEDUAN,ZAIGUANJIAOZIYUANFENGFUDEQINGKUANGXIA,WOTONGCHANGYULIUYIGEIOKOULIANJIEledHUOZHELABA,WEIXIAYIBURUANJIANDEBIANXIEZUOPUDIAN。ZAIQIANRUSHIXITONGYUNXINGGUOCHENGZHONGSHIDANGKONGZHIGAIIOJIEKOU,CONGERPANDUANXITONGSHIFOUZHENGCHANGYUNXING。

第四、外扩存储设备

YIGEQIANRUSHIXITONGRUGUOYOUDIANYUAN、JINGZHENHECPU,NEIMEZHEIJIUSHIWOMENSHUXIDEZUIXIAOXITONG。RUGUOGAIQIANRUSHIXITONGXUYAOYUNXINGDADIANDECAOZUOXITONG,NEIMEBUDANXUYAOCPUJUYOU MMU,CPUHAIXUYAOWAIJIESDRAMHENANDFLASH。RUGUOGAIcpuJUYOUSDRAMHENANDFLASHKONGZHIQI,NEIMEZAIYINGJIANSHEJISHANGBUYONGGUODUODEKAOLVDIZHIXIANDESHIYONG。RUGUOMEIYOUXIANGGUANDEKONGZHIQI,NEIMEXUYAOZHUYIDIZHIXIANDESHIYONG。

ZHEIBUFENZAILAYOUTDESHIHOUSHIYIGEZHONGDIAN,JIUQIYUANYINJIUSHIYAOSHIXIANGGUANXINHAOXIANDENGZHANGYIQUEBAOXINHAODEYANSHIXIANGDENG,SHIZHONGHEDQSDECHAFENXINHAOXIANZOUXIAN。ZAIBUXIANDESHIHOUGEZHONGBUXIANJIQIAOXUYAOZONGHESHIYONG,LIRUYUcpuDUICHENGFENBU,JUHUALIANBUXIAN、TXINGBUXIAN,ZHEIDOUXUYAOYIJUNEICUNDEGESHUDUOSHAOLAIJINXINGXUANZE,YIBANLAISHUOGESHUYUEDUO,BUXIANYUEFUZA,DANSHIZHIDAOQIGUANJIANDIAN,YIQIEYINGRENERJIE。

第五、功能接口

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第六、屏幕

ZHEIGEGONGNENGZHISUOYIDANDULIECHULAI,SHIYOUYUQIKEYOUKEWU。RUGUOYIGEQIANRUSHIXITONGZHISHIZUOWEIYIGELIANJIEQILIANJIEWAIWEISHEBEIMOKUAI,TONGGUOXIANGGUANJIEKOULIANJIEDAODIANNAOZHUJIHUOZHEZHIJIEGUAZAIWANGLUOSHANG,NEIMEPINGMUJIUBUXUYAOLE。DANSHIRUGUOZUOCHULAIDESHIYIGEXIAOFEILEICHANPIN,YUYONGHUJIAOHUPINFAN,ZHEIJIUBUDEBULAOTAOJIJU。

DIANRONGPINGMUSHIQIANRUSHIPINGMUDESHOUXUAN,ZAIDIANLUSHEJIZHONGXUYAOZHUYICHUPINGLIANJIEXIANHEXIANSHIPINGLIANJIEXIANDEBUJU。ZAIZOUXIANDEGUOCHENGZHONGJINLIANGDUANDEKAOJINZHUKONGcpu,TONGSHIZHUYIPEIDUIXINHAOZOUCHAFENXIAN,RGBKONGZHIXINHAOZOUDENGZHANG。GEZHONGXINHAOZOUXIANJIANJUZUNXUN3WGUIZE,BIMIANXIANGHUGANRAO。 ZAIPINGMUDESHEJIZHONG,YIDINGYAOQUEBAOGONGLVHEFANGZHIGANRAO,YIFANGPINGMUSHANPINGHEHUAPINGXIANXIANGDECHUXIAN。


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