Master to Master String - Gibberish

jabramson · July 2013

I have a master to master connection and I can see the String From correctly on the second master. However when I'm assigning that to a variable via DATA.TEXT on Master 2 I am just get gibberish. The firmware is the same on both units. Why would this be?

ericmedley · July 2013

Check the variable type you are assigning as your string buffer. My guess is that the string coming in as not ASCII. So, the hex values coming in are being represented as ASCII.

jabramson · July 2013

It is a hex string coming in. How do I convert that to something useful? I only see HEXTOI, but this does contain ASCII as well.

dhasley · July 2013

If you want to just look at it live, the debugger in NetLinx Studio can be set to display the hex values. If you want to print it out to the terminal or elsewhere, you'll need to write something to change each byte to an ASCII string, e.g., convert the following single example byte: "$02" into a three byte ASCII string: '$02' (shown in hex: "$24,$30,$32"), then send it to the terminal. Here's an example:

DEFINE_FUNCTION CHAR[100] fnStringToHex(CHAR cInString[])
{
LOCAL_VAR CHAR cTempByte;
LOCAL_VAR CHAR cTempString[2];
LOCAL_VAR CHAR cOutString[100];

CLEAR_BUFFER cOutString;

WHILE(LENGTH_ARRAY(cInString))
{
cTempByte = GET_BUFFER_CHAR(cInString); //Grab one byte from the input
cTempString = ITOHEX(cTempByte); //Convert that one byte to a two byte string representing the hex value in ASCII
IF(LENGTH_ARRAY(cTempString) == 2)
{
cOutString = "cOutString,'$',cTempString,','"; //Add a dollar sign to the beginning and a comma to the end, for readability
}
ELSE IF(LENGTH_ARRAY(cTempString) == 1)
{
cOutString = "cOutString,'$0',cTempString,','"; //Pad with a zero if the output of ITOHEX was ony one character long
}
}

SET_LENGTH_ARRAY(cOutString,LENGTH_ARRAY(cOutString) - 1); //Discard the last comma
cOutString = "'"',cOutString,'"'"; //Add some quotes, because I want them in the string I'll be passing to my terminal

RETURN cOutString; //Return the finished string - enjoy!
}

ericmedley · July 2013

jabramson wrote: »

It is a hex string coming in. How do I convert that to something useful? I only see HEXTOI, but this does contain ASCII as well.

Well, what's not useful about hex? For example, let's make up a protocol for the discussion. Let's say the string coming back is a mix of hex and ascii.

Let's say the box comes back with the following string for a change in volume.

"$01,$01,$02,DVD:45,$FF" The first threer cells are bytes telling you the
unit ID
Power Stat
Zone Id
The given ASCII text name of the zone
The ASCII value of the volume
and the $FF is the string terminator.

Treat cells 1 through 3 as integers

So unit ID is something like..

integer Unit_id;
integer Power_Stat;
integer Zone_id;

Unit_ID=buffer[1]
Power_Stat=buffer[2]
Zone_id=buffer[3]

there are many ways to do this and this is just an example for the sake of the discussion.

To get the text out just strip out the first three cells of the buffer. use Right String or Get_Buffer_Char or whatever. or search for the first hex value in the string over $20 which is where the ASCII chars start.

So something like.

DEFINE_Variable
Zone_Name[10]

GET_BUFFER_CHAR(buffer)// strips off first buffer cell
GET_BUFFER_CHAR(buffer)// next cell
GET_BUFFER_CHAR(buffer)// next cell
Zone_Name=remove_string(buffer,':',1) // Zone_Name will be "DVD:"
// then strip off the last ":" and you'll have your text.

now all that's left is "45,$FF"

so to get the volume from the ascii value is easy-peasy.

DEFINE_VARIABLE
integer current_vol

current_vol=atoi(buffer)

Hope that helps.
e

Joe Hebert · July 2013

FORMAT plug

dhasley wrote: »

If you want to just look at it live, the debugger in NetLinx Studio can be set to display the hex values. If you want to print it out to the terminal or elsewhere, you'll need to write something to change each byte to an ASCII string, e.g., convert the following single example byte: "$02" into a three byte ASCII string: '$02' (shown in hex: "$24,$30,$32"), then send it to the terminal. Here's an example:

DEFINE_FUNCTION CHAR[100] fnStringToHex(CHAR cInString[])
{
LOCAL_VAR CHAR cTempByte;
LOCAL_VAR CHAR cTempString[2];
LOCAL_VAR CHAR cOutString[100];

CLEAR_BUFFER cOutString;

WHILE(LENGTH_ARRAY(cInString))
{
cTempByte = GET_BUFFER_CHAR(cInString); //Grab one byte from the input
cTempString = ITOHEX(cTempByte); //Convert that one byte to a two byte string representing the hex value in ASCII
IF(LENGTH_ARRAY(cTempString) == 2)
{
cOutString = "cOutString,'$',cTempString,','"; //Add a dollar sign to the beginning and a comma to the end, for readability
}
ELSE IF(LENGTH_ARRAY(cTempString) == 1)
{
cOutString = "cOutString,'$0',cTempString,','"; //Pad with a zero if the output of ITOHEX was ony one character long
}
}

SET_LENGTH_ARRAY(cOutString,LENGTH_ARRAY(cOutString) - 1); //Discard the last comma
cOutString = "'"',cOutString,'"'"; //Add some quotes, because I want them in the string I'll be passing to my terminal

RETURN cOutString; //Return the finished string - enjoy!
}

As the official spokesman for FORMAT, I feel compelled to point out that the variable cTempString and this code:

cTempString = ITOHEX(cTempByte); //Convert that one byte to a two byte string representing the hex value in ASCII
IF(LENGTH_ARRAY(cTempString) == 2)
{
cOutString = "cOutString,'$',cTempString,','"; //Add a dollar sign to the beginning and a comma to the end, for readability
}
ELSE IF(LENGTH_ARRAY(cTempString) == 1)
{
cOutString = "cOutString,'$0',cTempString,','"; //Pad with a zero if the output of ITOHEX was ony one character long
}

Can be replaced with this 1 line using the underappreciated FORMAT command:

cOutString = "cOutString,FORMAT('$%02X,',cTempByte)"

Exit stage left...

Master to Master String - Gibberish

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