Converting canID to hex

Projects Networking, Protocols, and Devices
1

I am trying to take the decimal ID provided by CAN.getCanId() and put it in hex.
I am doing:

char buffer[1];
itoa (CAN.getCanId(),buffer,16);

but I only get the last 4 digits of the hex ID instead of all 8 (29-bit ID)
I'm guessing iota can only handle 16 bits of an input integer?

2

Problem solved.
I come from vb.net so I'm sure this isn't the most efficient way, but it works!

char shortID[4];
String completeID;
int canIDhigh = (CAN.getCanId() & 0xFFFF0000) >> 16;
int canIDlow = CAN.getCanId() & 0x0000FFFF;

itoa (canIDhigh,shortID,16);
completeID = shortID;
itoa (canIDlow,shortID,16);
completeID = completeID + shortID;
Serial.println(completeID); //Voila!

3

What about Serial.println(number, HEX);

...R

4

Actually, while that's great and easy, it only works for outputting to the serial port. I need to use this code internally.

5 
char buffer[1];
itoa (CAN.getCanId(),buffer,16);

The itoa() function adds a NULL terminator. Leaving room in the array for that, how much room is there for your data?

6

Even if I did a length of 33, it would only do the 4 hex chars. Making size 1, you would think it would truncate it, but it didn't.

7

OK, for building the data string, I did this:

datastring = datastring + String(buf*,HEX);*

8

Even if I did a length of 33, it would only do the 4 hex chars. Making size 1, you would think it would truncate it, but it didn't.

I would NOT think that. What, EXACTLY, does CAN.getCanId() return?

9

It returns the ID of the transmitted CAN packet in decimal form.

By doing this, I get the fully concatenated hex version of the ID, which is what I want:

long canID = CAN.getCanId();
int canIDhigh = (canID & 0XFFFF0000) >> 16;
int canIDlow = canID & 0X0000FFFF;
itoa(canIDhigh,shortID,16);
completeID = shortID;
itoa(canIDlow,shortID,16);
completeID += shortID;

10

It returns the ID of the transmitted CAN packet in decimal form.

Nonsense. If the function returns a long, or unsigned long, you be absolutely certain that the data is in BINARY.

And, you can be sure that ltoa() (long to ASCII) can convert the value to a string in one step.

11

PaulS:
Nonsense. If the function returns a long, or unsigned long, you be absolutely certain that the data is in BINARY.

And, you can be sure that ltoa() (long to ASCII) can convert the value to a string in one step.

it comes back as a unsigned long.

12

phuz:
it comes back as a unsigned long.

What does? If you are referring to the value from CAN.getCanId(), why are you then storing it in a long?