Re: Sending / receiving AV/C commands

[Andreas B. <and...@mu...>]

On Mon, Apr 03, 2000 at 03:20:08PM -0700, Timothy M. Shead wrote:
> // Write the command ...
> raw1394_write(m_Handle, 0xffc0 | m_Node, FCP_COMMAND_ADDR, 4, &Command);
> 
> // Wait for a result ...
> quadlet_t result;
> raw1394_read(m_Handle, 0xffc0 | m_Node, FCP_RESPONSE_ADDR, 4, &result);
> while((result & 0x0F000000) == 0x0F000000)
>   {
>     std::cerr << "sdpAvcSubUnit::RawCommand() waiting for response!" <<
> std::endl;
>     result = raw1394_read(m_Handle, 0xffc0 | m_Node, FCP_RESPONSE_ADDR, 4,
> &result);
>   }
> 
> ... the write works, but "read" is entering an infinite loop.  Any thoughts
> on what I'm doing wrong?  In the meantime, the library and a couple of
> sample apps will be posted later today on my website, www.k-3d.com.

From what I have read about FCP communication the response is sent to
the local FCP_RESPONSE register.  And you can't read that out
directly, you have to set up a FCP handler in libraw1394.

See testlibraw.c in libraw1394 0.6 for an example.

-- 
 Andreas E. Bombe <and...@mu...>    DSA key 0x04880A44
http://home.pages.de/~andreas.bombe/    http://linux1394.sourceforge.net/