u-boot调试方法：设置CPU引脚为串口启动，然后通过超级终端，发送u-boot-spl.bin，u-boot-spl.bin执行到s_init()中的sdram_init后，串口界面就没有C字符输出了，初步怀疑为SDRAM初始化参数错误，请问各位大神，这个判断对吗？另外DDR3参数如何确定呢？内存用的是micron的MT41K512M8
以下是DDR相关参数定义：
#define MT41K512M8RG_EMIF_READ_LATENCY 0x7
#define MT41K512M8RG_EMIF_TIM1 0x888a39b
#define MT41K512M8RG_EMIF_TIM2 0x2a517fda
#define MT41K512M8RG_EMIF_TIM3 0x501f84ef
#define MT41K512M8RG_EMIF_SDREF 0x0000093B
#define MT41K512M8RG_EMIF_SDCFG 0x4C000008
#define MT41K512M8RG_RD_DQS 0x40
#define MT41K512M8RG_WR_DQS 0x9
#define MT41K512M8RG_PHY_FIFO_WE 0x7F
#define MT41K512M8RG_PHY_WR_DATA 0xC1
#define MT41K512M8RG_IOCTRL_VALUE 0x18B
#define MT41K512M8RG_ZQ_CFG 0x50074BE4
#define MT41K512M8RG_RATIO 0x80
#define MT41K512M8RG_INVERT_CLKOUT 0x0
