{*****************************************************************************
 *                     SAMPLE4.PAS : D to A OUTPUT                           *
 *                                                                           *
 *  This is a demonstration program to be used with the AD12-16 A/D          *
 *  board.  The program will prompt the user for a voltage, output it to D/A *
 *  channel 0, then read the voltage back in on channel 0.                   *
 *                                                                           *
 *  The board should be set as follows:                                      *
 *      -- IRQ5 is used for interrupts                                       *
 *      -- Polarity set to bipolar                                           *
 *      -- DMA channel 1                                                     *
 *      -- On board clock set to 1 MHz                                       *
 *                                                                           *
 *  A jumper is required from pin 8 to pin 10.                               *
 *  A jumper is required from pin 9 to pin 37.                               *
 *                                                                           *
 *  LAST MODIFICATION: 2/3/98                                                *
 *                                                                           *
 *****************************************************************************}
program startup;
{$L a16drv}
{$F+}

USES crt;

type param_array = array[1..5] of integer;

{ all of the parameters passed to the A16DRV driver must be declared
 globally, including the buffers which have their offset passed inside
 the params array }

var  task,status        : integer;
     params             : param_array;
     ch                 : char;

procedure a16drv(t_off:word;p_off:word;st_off:word);external;


function AskForBaseAddress(OldOne : String) : Word;
const
   Msg : string[4] = '0';
var
   NewOne, Success, Dummy, Error : Word;
   AddrInputPosX, AddrInputPosY : Word;
begin
   if (OldOne = 'OLD') then OldOne := Msg;
   WriteLn('Please enter the Base Address (0000-FFFF) for your card (in hex)');
   WriteLn('or press ENTER for ', OldOne, '.  ');
   Write('>');
   AddrInputPosX := WhereX; AddrInputPosY := WhereY;
   repeat
      GotoXY(AddrInputPosX, AddrInputPosY);
      ClrEol;
      Readln(Msg);
      Val('$' + Msg, NewOne, Error);
      if (error=0) then begin
         Success := 1;
         Dummy := NewOne;
      end else if (Msg = '') then begin
         GotoXY(AddrInputPosX, AddrInputPosY);
         WriteLn(OldOne);
         Msg := OldOne;
         Success := 1;
         Val('$' + Msg, Dummy, Error);
      end;
   until (Success = 1);
   AskForBaseAddress := Dummy;
end;  { end of AskForBaseAddress }



{***************************************************************************
 * PROCEDURE: call_driver -- local routine                                 *
 *                                                                         *
 *   PURPOSE: Performs the call to the driver package.                     *
 *                                                                         *
 *     INPUT: None.                                                        *
 *                                                                         *
 *     CALLS: a16drv - entry point to driver package.                      *
 *                                                                         *
 *    OUTPUT: None.                                                        *
 *                                                                         *
 ***************************************************************************}
procedure call_driver;

var t_off,p_off,st_off : word;

begin

   { this section extracts the offset of the parameters that we will pass
      to the assembly driver }

   t_off := ofs(task);
   p_off := ofs(params[1]);
   st_off := ofs(status);
   status := 0;
   a16drv(t_off,p_off,st_off);

   { this section checks for an error code  }

   if status > 0 then
      begin
      WriteLn('A status error code of ',status,' was detected.');
      WriteLn('Program terminated.');
      end;
end; { call_driver }

{*****************************************************************************
 *  FUNCTION: setup -- local routine                                         *
 *                                                                           *
 *   PURPOSE: Sets up the driver package to read channel 0.                  *
 *                                                                           *
 *     INPUT: None.                                                          *
 *                                                                           *
 *     CALLS: call_driver - entry point to driver package.                   *
 *                                                                           *
 *    OUTPUT: Returns the error code supplied by the driver routine.         *
 *                                                                           *
 *****************************************************************************}
procedure setup(Address:word);

var I              :integer;

begin

   { initialize the board }

   task := 0;
   params[1] := Address; { starting board address }
   params[2] := 5;       { IRQ5 }
   params[3] := 1;       { DMA channel 1 }
   call_driver;          { call routine to call ext module }
   if status <> 0 then exit;
end; {procedure setup }

{*****************************************************************************
 *  FUNCTION: get_readings -- local routine                                  *
 *                                                                           *
 *   PURPOSE: Prompts for a voltage, writes it to D/A 0 and read A/D chan 0. *
 *                                                                           *
 *     INPUT: None.                                                          *
 *                                                                           *
 *     CALLS: call_driver - entry point to driver package.                   *
 *                                                                           *
 *    OUTPUT: Returns the error code supplied by the driver routine.         *
 *****************************************************************************}
procedure get_readings;

var volts             :real;
    I                 :integer;

begin
   ClrScr;

   { set the scan limits for channel 0 }

   task := 1;
   params[1] := 0;   { lower scan limit }
   params[2] := 0;  { upper scan limit }
   call_driver;      { call routine to call ext module }

   { fetch the voltage to output and calculate counts needed }
   WriteLn;WriteLn;
   write('Enter the voltage to output: ');
   readln(volts);
   volts := (volts / 5) * 4095;
   params[2] := trunc(volts);

   { write the counts to the D/A }

   task := 15;
   params[1]:= 0;
   call_driver;             { call routine to call ext module }
   if status <> 0 then  exit; { if status > 0 then error }

   { delay for a little }

   I := 0;
   while I < 1000 do I:=I+1;

   { read the A/D channel 0 }

   task := 3;
   call_driver;

   { now compute the proper volts from the counts }
   volts := (params[1] / 2047) * 5;
   WriteLn;
   WriteLn('The value read back is:',volts:8:3);
end; { get_readings }

{**************************************************************************
 * PROCEDURE: main -- local routine                                       *
 *                                                                        *
 *   PURPOSE: Controls program flow, detects when user is ready to exit.  *
 *                                                                        *
 *     INPUT: None.                                                       *
 *                                                                        *
 *     CALLS: setup - set up program and drivers.                         *
 *            get_readings - read the A/D channels and display.           *
 *                                                                        *
 *    OUTPUT: None.                                                       *
 *                                                                        *
 **************************************************************************}
var
   Address:word;

BEGIN
   ClrScr;
   WriteLn('                        SAMPLE4.PAS : DAC Output');
   WriteLn;
   WriteLn('This is a demonstration program to be used with the AD12-16 A/D');
   WriteLn('board.  The program will prompt the user for a voltage, output it to D/A');
   WriteLn('channel 0, then read the voltage back in on channel 0.');
   WriteLn;
   WriteLn;
   Address := AskForBaseAddress('350');

   ClrScr;
   WriteLn;
   WriteLn;
   WriteLn;
   WriteLn('Board Configuration:');
   WriteLn;
   WriteLn(' -- IRQ5 is used for interrupts              (required)');
   WriteLn(' -- Polarity set to bipolar                  (required)');
   WriteLn(' -- Range is from 0 to 5 volts               (required)');
   WriteLn(' -- DMA channel 1                            (required)');
   WriteLn(' -- On board clock set to 1 MHz              (required)');
   WriteLn(' -- A jumper is required from pin 8 to pin 10.');
   WriteLn(' -- A jumper is required from pin 9 to pin 37.');
   WriteLn(' -- All remaining jumper settings are irrelevant.');
   WriteLn;
   WriteLn;
   WriteLn;
   WriteLn;
   WriteLn('Press any key to continue, or press E to exit.');
   ch := ReadKey;
   setup(Address);         { set up program and the driver }
   while (status = 0) and (ch <> 'E') and (ch <> 'e') do
      begin
      { display current values for the 8 channels }
      get_readings;
      if status = 0 then
         begin { if status > 0 then error }
         { check for program exit }
         WriteLn;
         WriteLn('Press E to exit program.  Any other key to continue...');
         ch:=ReadKey;     { wait for key press }
         end;
      end;
END. { main program }