Watchdog that should be taken out and shot

I've been trying to implement the watchdog timer on my Sharp79524 and it
appears that the mutt is sleeping on the job!

I believe I have it set up to trigger after about 3s of inactivity but
it doesn't seem to reset the system at all.

My setup method is as follows:
1) Write 0x00000090 to the watchdog CTL to set up for 2^25 counts of
HCLK as the timeout period. This also stops an interrupt on first
timeout occurring and should set up for an immediate reset. Watchdog not
enabled at this point

2) Write 0x1984 to the watchdog RST register to seed the counter.
(Goodness knows why they chose that value)

3) OR 0x00000001 onto the CTL register to enable the watchdog.

4) OR 0x00000008 onto the CTL regsiter to lock the enable.

Then I periodically write Ox1984 to the RST register to keep everything
alive.

Then if I encounter a while(1); that I've planted somewhere then the
system hangs but no reset ever happens.

Is there something I've missed? The watchdog section of the user guide
was only a few pages so it would appear to be "simple" but perhaps there
are other things that affect it's operation?

I've tried running under the debugger and also stand-alone from flash in
case that made any difference but it doesn't seem to.

Any ideas?


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