c ----------------------------------------------------------------------
c Test A/D converter directly from FORTRAN by manipulating the I/O ports
c The main program is exactly the same as AD.FOR
c Link with ASM.OBJ only (no ADDA.OBJ)
c ----------------------------------------------------------------------

      character text*10,ascii

c Voltage limits = -10V -- +10V --> range=20.
      range  = 20.
      factor = range/4096.

c Reset the A/D converter
      CALL RESADC

5     call clrscr
      call output(4,5,'Hit any key to change channel.$')
      call output(5,5,'Enter channel # (0-15 for SE, or 0-7 for DI): $')
      read(*,501)ichan
      call output(6,5,'Enter gain (0=X1, 1=X2, 2=X4 3=X8): $')
      read(*,501)igain
      call output(7,5,'Voltage: $')

10    CALL ADIN00(ICHAN,IGAIN,IVALUE)
      voltage=float(ivalue-2048)*factor
      write(text,605)voltage,'$'
      call output(7,14,text)
      call askkey(iyesno)
      if(iyesno .eq. 0)goto 10

      call readky(ascii,iscan)
      goto 5

501   format(i5)
502   format(f8.3)
605   format(f8.3,a1)
      end


      SUBROUTINE RESADC
c Reset the A/D board directly from FORTRAN
c   dport ... Data port
c   cport ... Command port

      integer*2 chan,gain,value,dport,cport
      dport=#2EC
      cport=#2ED

c Issue a Stop Command
      call outp(cport,15)

c Kill some time (i.e. 9 ticks)
      call gettic(ihword,ilword)
      iold = ilword
5     call gettic(ihword,ilword)
      if(ilword .lt. iold+9)goto 5

c Take a look at at the Status bit 1: read from the Data Register
c   so that bit 1 can be cleared
      call inp(cport,iovalue)
      ibit0=mod(iovalue,2)
      if(ibit0 .eq. 1)call inp(dport,iovalue)

c Check to make sure that bit 2 is set before writing to the Command Register
c Bit 2 has a value of 4
10    call inp(cport,iovalue)
      ibit2=mod(iovalue/4,2)
      if(ibit2 .eq. 0)goto 10

c Select Function 1: Clear Error
      call outp(cport,1)

      return
      end


      SUBROUTINE ADIN00(CHAN,GAIN,VALUE)
c Perform A/D conversion directly in FORTRAN
c   dport ... Data port
c   cport ... Command port

      integer*2 chan,gain,value,dport,cport
      dport=#2EC
      cport=#2ED
      value=0

c Check to make sure that bit 2 is set before writing to the Command Register
c Bit 2 has a value of 4
10    call inp(cport,iovalue)
      ibit2=mod(iovalue/4,2)
      if(ibit2 .eq. 0)goto 10

c Select Function 12: Read A/D Immediate
      call outp(cport,12)

c Check to make sure that bit 1 is 0 before writing to the Data Register
20    call inp(cport,iovalue)
      ibit1=mod(iovalue/2,2)
      if(ibit1 .eq. 1)goto 20

c Write GAIN to the Data Register
      call outp(dport,gain)

c Check to make sure that bit 1 is 0 before writing to the Data Register
30    call inp(cport,iovalue)
      ibit1=mod(iovalue/2,2)
      if(ibit1 .eq. 1)goto 30

c Write CHAN to the Data Register
      call outp(dport,chan)

c Check to make sure that bit 0 is set before reading from the Data Register
40    call inp(cport,iovalue)
      ibit0=mod(iovalue,2)
      if(ibit0 .eq. 0)goto 40

c Read the low byte from the Data Register
      call inp(dport,value)

c Check to make sure that bit 0 is set before reading from the Data Register
50    call inp(cport,iovalue)
      ibit0=mod(iovalue,2)
      if(ibit0 .eq. 0)goto 50

c Read the hi byte from the Data Register
      call inp(dport,iovalue)
      value=iovalue*256 + value

      return
      end