How to get rid of the "fade in" of PA/F on DA830?

I am now running the PA/F I12 topology under Linux on the ARM of DA830. I have used execPAIInRingIO and execPAIOutAnalog, and I have sent writeVOLControlMasterN(0) and writePCMRampDisable. However I still hear the sound "fades in" each time when I execute "./pad pcm a.wav". How can I make the sound be in the normal volume at the very beginning? Thanks!