Get Seed & unlock

Question

Hi,
I'm using an ECU board fo test with CAN interface.Since ECU has security lock in it i'm trying to unlock the protection(using GET Seed and Unlock Protection commands)As Get seed provides the Seed data,for computing the Key i'm using a DLL SeedKey1.dll(supplied by our customers) and then passing the key value to the Unlock Vi.But during course of my execution,program stops at Seedkey1.dll and throws an exception mentioning that exception occured at specified node(screen shot of which i have attached)
The function prototype for Seedkey dll specified is
unsigned long SEEDKEYAPI ASAP1A_CCP_ComputeKeyFromSeed(
  unsigned char *seed,
  unsigned short sizeSeed,
  unsigned char *key,
  unsigned short maxSizeKey,
  unsigned short *sizeKey);
The reason i need to unlock is for performing my CCP read and Tuning some EEPROM values of ECU.The sequence in which i'm using Get Seed is 1.CCP Open(with timeout)->.CCP Connect->CCP Get Seed
The attachments for reference which i have provided with this under a folder named  "Files" are
1.subvi which i'm using for Unlock after CCP Connect
2.screenshot of error occured when i run my application and try to perform CCP Read.
3.Seedkey dll which i'm using
one more additional info which i want to add is that in the Get Seed.vi ,i have given Resource input as 1.Is that a valid one if i want to perform a CCP Read.
A reply for this will be really of helpful to me.
Regards
Murali
Attachments:
Files.zip ‏37 KB

Answer 1

Hi Murali,
I have no experience with the DLL you are using, but from the LabVIEW end, I can tell you that exceptions generated in external DLLs are normally due to memory management.  That is, it's likely that the DLL you are calling is throwing an exception because of a memory access violation (null pointer read?), it is out of memory, etc.  You could look at the code with this in mind.
You may also find this tutorial on Accessing DLLs or Shared Libraries from LabVIEW helpful.
Good luck!
Megan B.
National Instruments