3)DDR检测
RTD芯片方案的主板,因在开机时没有DDR初始化这一步,所以,维修工程师容易造成误判,即引导偏移地址的DDR电路有故障,开机会出现无打印信息,若几秒钟后显示如图42中的两段打印信息,均为主芯片顶部DDR电路有故障,直接对应检查即可。
若出现如图43所示的打印信息,则为EMMC通讯故障。
若内核和主程序偏移地址的DDR电路发生故障,可以正常开机,但会卡在开机LOGO画面,这种故障软件和硬件均有可能,若采取软件升级不行的话,那基本就是DDR电路问题。
换另一种方式:只要输入下面一段命令,即可快速判断是硬件还是软件问题。
mtest 0x40000000 0x41000000 all 100
若出现如图44所示信息(DDR检侧正常),那就是软件问题,直接升级软件即可。
若出现如图45所示不停地跑错误信息,则为内核和主程序偏移地址DDR电路故障,也就是主芯片左侧两片DDR电路有故障,此时就不要再去升级软件,直接检查主芯片左侧两片DDR电路即可。
(4)安卓控制台下修改屏参(MT5505、MT5326、MT5502芯片方案)
主板完全启动后,在Securc CRT窗口敲回车,出现的命令行内输入“cli”后再敲回车,如图46所示。
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