subroutine hec_fadc_unpk
c
c read event header from epio block
c
      implicit none
c
c geometry correspondence tables common
c must be preceded by the include file hec_par.inc
c
      include'hec_par.inc'
      include'hec_geo.inc'
c
c adc values common
c
      include'hec_fadc.inc'
c
c local variables
c
      integer i_t
      integer ipat1, ipat2, imod, iw, iwstart, iwend
c
c unpack bits and fill common. 
c
      do imod = 1, n_fadc_mod
         if (imod .eq. 1) then
            iwstart = 2
            iwend = 2*i_fadc_tim
         elseif (imod .eq. 2) then
            iwstart = 2*i_fadc_tim + 2
            iwend = 4*i_fadc_tim
         endif
         do iw = iwstart, iwend, 2
            ipat1 = i_fadc_pk(iw-1)
            ipat2 = i_fadc_pk(iw) 
c     
c make binary into actual channel numbers and adc values
c first 8 bits are channel, then 12 bits for even numbered 
c channel followed by 12 bits for odd numbered channel.
c ibits is from cernlib Kernlib M441. It translates a certain
c bit range in a word into an integer (counts right to left).
c
c
            if (imod .eq. 1) i_t = iw/2
            if (imod .eq. 2) i_t = iw/2 - iwstart/2 + 1
            i_fadc_ic_t(4*imod-3,i_t) = ibits(i_fadc_pk(iw),0,8)
            i_fadc_ic_t(4*imod-2,i_t) = ibits(i_fadc_pk(iw),8,8)
c     
            i_fadc_ic_t(4*imod-1,i_t) = ibits(i_fadc_pk(iw-1),0,8)
            i_fadc_ic_t(4*imod,i_t) = ibits(i_fadc_pk(iw-1),8,8)
c
c print debug
c
ccc          print *, 'ipat1:2 -->',ipat1,ipat2
ccc          print *, 'fadc,ic,t',i_fadc_ic_t(4*imod-3,i_t),4*imod-3,i_t
ccc          print *, 'fadc,ic,t',i_fadc_ic_t(4*imod-2,i_t),4*imod-2,i_t
ccc          print *, 'fadc,ic,t',i_fadc_ic_t(4*imod-1,i_t),4*imod-1,i_t
ccc          print *, 'fadc,ic,t',i_fadc_ic_t(4*imod,i_t),4*imod,i_t
c
         enddo
      enddo
c
c
c     print *,' *** fadc data unpacked'
c
      end