How to get CIR by using dwt_readaccdata in DecaRangeRTLS

Hello Everyone,
I’m developing in DecaRangeRTLS, and using dwt_readaccdata method to read and plot CIR, but failed.
This is my code:

float lym_amp[1000];//store amplitude
for (int var = 0; var < 1000; var++) {
uint8 data[5];
dwt_readaccdata(&data[0], 5, 4*var);
imag = (uint16)(data[2]<<8) | data[1];
real = (uint16)(data[4]<<8) | data[3];
lym_amp[var] = sqrt((float)real*real + (float)imag*imag);

I consider the dummy octet. Is something wrong?

Any kind of help is much appreciated.