uses crt, commdrv;

const
  base = $300;

var
  retString, ch : String;

procedure ErrorCheck(CheckString:string);
   begin
      if CheckString = '??ERROR!' then
         begin
            WriteLn ('Sorry, there has been a pod communication error!');
            halt;
      end;
   end;

begin
   ClrScr;

{H}
   WriteLn('Press a key to say hello to pod...');
   ch := readkey;
   initcommcard(base, 9600);
   writepod(base, 'H');
   readpod(base, retString);
   WriteLn(retstring);
   if retstring = '??ERROR!' then
   begin
      WriteLn ('Sorry there has been a pod communication error!');
      WriteLn ('Your pod must be set to baud 9600.');
      halt;
   end;

{M}
   WriteLn('Press a key configure all the bits as inputs...');
   ch := readkey;
      {bits 0-7 input}
   writepod(base, 'ML00');
   readpod(base, retString);
   ErrorCheck(retstring);
   delay(50);

      {bits 8-F input}
   writepod(base, 'MM00');
   readpod(base, retString);
   ErrorCheck(retstring);
   delay(50);

      {bits 10-17 input}
   writepod(base, 'MH00');
   readpod(base, retString);
   ErrorCheck(retstring);

{I}
   WriteLn('Press a key to read all the bits...');
   ch := readkey;
      {read all bits}
   writepod(base, 'I');
   readpod(base, retString);
   ErrorCheck(retstring);
   WriteLn('The twenty-four bits are ',retString);

   WriteLn('Press a key to read bit 0F...');
   ch := readkey;
      {read bit 15}
   writepod(base, 'I0F');
   readpod(base, retString);
   ErrorCheck(retstring);
   WriteLn('Bit 0F is ',retString);

   WriteLn('Press a key to read bits 0-7...');
   ch := readkey;
      {read bits 0-7}
   writepod(base, 'IL');
   readpod(base, retString);
   ErrorCheck(retstring);
   WriteLn('Bits 0-7 are ',retString);

{M}
   WriteLn('Press a key to configure all the bits as outputs... ');
   ch := readkey;
      {bits 0-7 output}
   writepod(base, 'MLFF');
   readpod(base, retString);
   ErrorCheck(retstring);

      {bits 0-7 output}
   writepod(base, 'MLFF');
   readpod(base, retString);
   ErrorCheck(retstring);

      {bits 0-7 output}
   writepod(base, 'MLFF');
   readpod(base, retString);
   ErrorCheck(retstring);

{F}
   WriteLn('Press a key to create a Free-Running square wave (bit 0F period 10)...');
   ch := readkey;
      {Free-Running square wave on bit 0F with period 10}
   writepod(base, 'f0F,10');
   readpod(base, retString);
   ErrorCheck(retstring);

{C}
   WriteLn('Press a key to read digital input counter 0F...');
   ch := readkey;
      {read digital input counter 0F}
   writepod(base, 'c0F');
   readpod(base, retString);
   ErrorCheck(retstring);
   WriteLn('The value of the digital input counter is ',retString);

{R}
   WriteLn('Press a key to end free run...');
   ch := readkey;
      {turn off free run}
   writepod(base, 'r0F');
   readpod(base, retString);
   ErrorCheck(retstring);

{S}
   WriteLn('Press a key to set time base to 1 KHz...');
   ch := readkey;
      {set time base}
   writepod(base, 'S039A');
   readpod(base, retString);
   ErrorCheck(retstring);
   delay(100);

{O}
   WriteLn('Press a key to write a 0 to bit 2...');
   ch := readkey;
      {write a zero to bit 2}
   writepod(base, 'O2-');
   ErrorCheck(retstring);
   readpod(base, retString);

   WriteLn('Press a key to write a 1 to bit 3...,');
   ch := readkey;
      {write a one to bit 3}
   writepod(base, 'O3+');
   ErrorCheck(retstring);
   readpod(base, retString);

   WriteLn;
   WriteLn;
   WriteLn('You have completed the RDG-24 Sample 1 program.');

end.