Parsing Hex Responses

screenscribe · January 2009

I'm working through my first module for a TOA 9000 series Mixer/Amp. I've setup a buffer in DEFINE_START to catch responses from the device.

Will each individual element in my CHAR array buffer be able to carry any HEX value from 00 to FF?

To illustrate this...let's say the device were to return 91H, 03H, 00H, FFH, 00H. Let's just say nothing else is in the buffer. Would it look like this?

MyBuffer[1] = $91
MyBuffer[2] = $03
MyBuffer[3] = $00
MyBuffer[4] = $FF
MyBuffer[5] = $00

Cheers,
Matthew

TurnipTruck · January 2009

MyBuffer[1] = "$91"

and you may say:

If (MyBuffer[1]="$91")
  //Do Something

Joe Hebert · January 2009

screenscribe wrote:

Will each individual element in my CHAR array buffer be able to carry any HEX value from 00 to FF?

Yes.

screenscribe wrote:

To illustrate this...let's say the device were to return 91H, 03H, 00H, FFH, 00H. Let's just say nothing else is in the buffer. Would it look like this?

MyBuffer[1] = $91
MyBuffer[2] = $03
MyBuffer[3] = $00
MyBuffer[4] = $FF
MyBuffer[5] = $00

Yes.

trav · January 2009

I want to be a mongoose.

screenscribe · January 2009

Thanks guys! I really appreciate the help.

Cheers,
Matthew

AMXJeff · January 2009

Parsing Help

This is how I would parse this...

DEFINE_DEVICE
dvTOA = 5001:1:0
DEFINE_VARIABLE

CHAR cBuffer[255];
CHAR cCMD;
CHAR cDataLength;
CHAR cData[100];


DEFINE_FUNCTION ParseMessage(CHAR cCmd, CHAR cData[])
{
	SWITCH (cCmd)
	{
		// Channel Fader Gain (Position)
		CASE $91:
		{
		}
		// Channel Fader Gain (Step)
		CASE $93:
		{
		}
		// Crosspoint Gain
		CASE $95:
		{
		}
		// Preset Memory Recall
		CASE $f1:
		{
		}
	}
}

DEFINE_START

CREATE_BUFFER dvTOA,cBuffer;

DEFINE_EVENT

DATA_EVENT[dvTOA]
{
	STRING:
	{
		// Buffer Trash Cleaning
		// Just for Sanity sake, do not expect this code to run.
		// FIRST BYTE IS NOT A COMMAND BYTE ($80 - $FF)
		WHILE (LENGTH_STRING(cBuffer) > 0 && cBuffer[1] < $80)
			GET_BUFFER_CHAR(cBuffer);
			
		// MAKE SURE WE STILL HAVE LENGTH
		IF (LENGTH_STRING(cBuffer) > 1)
		{
			// GET COMMAND BYTE
			cCMD = GET_BUFFER_CHAR(cBuffer);
			
			// GET LENGTH BYTE
			cDataLength = GET_BUFFER_CHAR(cBuffer);
			
			// Check to make sure we have length
			IF (cDataLength > 0 && LENGTH_STRING(cBuffer) >= cDataLength)
			{
				// Get the data
				cData = GET_BUFFER_STRING(cBuffer, cDataLength);
				
				// Parse the message
				ParseMessage(cCMD, cData);
			}
			// Not enough data, put humpty back together
			ELSE
			{
				cBuffer = "cCMD, cDataLength, cBuffer";
			}	
		}
	}
}

screenscribe · January 2009

That's perfect, Jeff! Thanks so much for your code. That just saved me oodles of time banging my head against a wall trying to figure out how to work the buffer!

Thanks again!

Cheers,
Matthew

a_riot42 · January 2009

It is easy to forget that even though it looks like you are packing three characters into one array element, $FF is still just a character, or an integer, however you decide to look at it.
$41 <==> 65 <==> 'A' <==> 0100 0001
Paul

screenscribe · January 2009

Definitely. It is a bit of a shift for me to start working with Hex values. Even though I get what is going on from a representational perspective, I am just learning how that plays out when communicating back and forth with the device.

Cheers,
Matthew

Parsing Hex Responses

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