SOC

huchunjie2011

U-Boot SPL 2013.01.01 (Jan 19 2015 - 08:48:49)
3 p" `  u+ v& Q- O8 J9 u! ?, rBOARD : Altera SOCFPGA Cyclone V Board
& U/ ]" i- U' @7 W" E8 u/ V# c& b! \% ySDRAM: Initializing MMR registers
& ]9 Q5 R  c7 LSDRAM: Calibrating PHY
SEQ.C: Preparing to start memory calibration
( g8 d7 F7 k4 {  {, d0 PSEQ.C: CALIBRATION FAILED
% L+ _$ j& g/ K2 M( ?### ERROR ### Please RESET the board ###
以上是串口打印信息，求大神解读下什么情况会出现CALIBRATION失败
6 V* S$ S9 S+ m( O8 A2 S