[Discuss-gnuradio] Re: Bug due to halfband and Why are the resets removed

[Eric Blossom]

On Thu, Dec 08, 2005 at 04:54:16PM +0100, Martin Dvh wrote:
> The new halfbandfilter stuff broke the debug_counter.
> I think this minipatch is the solution.
> I found this because I also use a counter in the fpga and it broke when I 
> updated my sourcetree.

Thanks!

> I also wonder why all the resets are removed.
> Are all the registers reset in another way now?

They weren't *all* removed.  Just the ones that were causing a problem.
The right answer is to add yet another reset signal that handles all
the rest, and just toggle that one after the FPGA is loaded.  It's a
little bit complicated since the FX2 code has some knowledge of those
particular registers.

Currently we are running with two resets:  tx_dsp_reset and rx_dsp_reset.
These are designated to reset the appropriate half of the signal
processing chain in the FPGA.  This includes the corresponding FIFO.

In the past, they were also resetting the control registers (FR_*) that were
also sort of associated with that half of the signal processing.  That
was the behavior that was wrong.  Just because you wanted to reset the
FIFO, didn't mean that you wanted to completely hose all of the rest
of the configuration.  We also had a problem where one of the resets was
resetting the register that contained the resets...  That was why
initializing the Rx was hosing the Tx, or vice-versa (don't recall
which way it went.)

In the mean while, the registers that matter to me are getting zeroed
from the host code.  In your case, you may still want to still reset
your register with tx_dsp_reset and/or rx_dsp_reset.  Depends on your needs.

Eric