Dear Perl Monks, I need a help in Win32::API

I am working on a hardware test automation, The interface to hardware is Automotive Interface 4 (AI4 : USB to SENT) and the H/W manufacturer has provided a C DLL which exports set of functions to communicate with the hardware.

I am trying to import the C DLL via Win32::API module so i can automate the communication via perl.

I have a problem with one API ,KSENT_TX. This function requires a pointer to an array of unsigned char as one of its arguments.

The header file extern declarations(provided by the manufacturer) looks as follows:

MOD_EXTERN unsigned char _stdcall KSENT_TX(unsigned char channel, unsigned char *data, unsigned long cyclic);

I have problems passing the right values to this function. Perl.exe crashes every time I try executing my code. 

my $Tx = Win32::API::More->new( 'AID.dll', 'KSENT_TX', 'CPN', 'C');
 #### $^E is non-Cygwin only
  die "Error: $^E" if ! $Tx;
  #### or on Cygwin and non-Cygwin
die "Error: ".(Win32::FormatMessage(Win32::GetLastError())) if ! $Tx;
my $rettx = $Tx->Call(0, $data_ref, 1);

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I tried various methods to pass the array reference

my $data_ref = [0x81 , 0x55, 0x00, 0xE0];

or

my @data = (129,85,0,224);
my $data_ref = \@data;

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also

my $data_ref = pack ('C*', (0x81 , 0x55, 0x00, 0xE0));

All of it leads to the same PERL crash. I am a novice to PERL development so maybe I am missing something really basic here. Can you please help me with this problem

In reply to How to pass a pointer to an array of 'unsigned char' C data type with Win32::API by apeks_okad

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