Read a Hex number from serial and convert to GA or I/O

Hi,

Does anyone know if it possible to read a hex value from the serial port and convert to either a Group Address level or A System IO?

Here is my logic so far...

I have tried the HexStringToInt function but the value read from the serial port is not a string it's a number? right?

HEX STRING BEING SENT = AA 1A 55

Code:

readSerial(1, ReceivedString,#$55);

if (ReceivedString[1] = #$AA) then
  begin
    ...
    //Set value of 2nd byte in string to a variable
    value := ReceivedString[2];
    //Convert value to GA Level or SystemIO
    [code goes here]
    WriteLn('Recognised Command');
  end
else
  begin
    WriteLn('Unrecognised Command');
  end;

I worked out that if I send a valid HEX string I get "Recognised Command" in the logic window and if I send an invalid string I get "Unrecognised Command" in the logic window so I know that the if statement is comparing the value of ReceivedString[1] with #$AA...

I want to save the "1A" as a group address or system IO level... can be done?

 

You need to extract the hex characters you are after before calling the HexStringToInt function

define a string variable in the Types section:

hexString: array[0..2] of char;

then extract the approriate hex characters:

copy(hexString, receivedString, 4, 2);

then convert it

value := hexStringToInt(hexString);

 

I wrote this as poer your instructions but it seems to have made no difference. I would have thought this would set the value of a system IO tot eh hex value of "BlindInt"??

Code:

readSerial(1, ReceivedString,#$55);

if (ReceivedString[1] = #$AA)then
  begin
    copy(hexString, ReceivedString, 4, 2);
    BlindInt := hexStringToInt(hexString);
    SetIntSystemIO("Blind", BlindInt);
    WriteLn('Recognised Command');
  end
else
  begin
    WriteLn('Unrecognised Command');
  end;

 

I think the confusion here might be your idea of a hex string. I think what you have really is a binary string. A hex string is a sequence of ascii characters in the range 0-9 and A-F where each pair of characters represents a single 8 bit byte. In your case it appears you are actually receiving the 8 bit bytes, not the ascii hex equivalent, so you are receiving a 3 byte string. If this is the case, you just extract it directly:

value := ord(receivedString[2]);

 

Thanks Ashley

Nailed it! Works perfect