You can't. The PLL feeds the internal clock. It can't be bypassed.

If you want to single step you *must* use the TAP (Test Access Port)
which is JTAG derived.

There is no other way to do this.

bigwayne@techie.com wrote:
> Does anyone know if the internall PLL on an Intel 80486 can be
> by-passed or disabled?

Doubtful unless it's a fully-static core.

> I want to single step using an externally controlled clock without the
> PLL.
> 
> Thanks,
> Wayne

Does anyone know if the internall PLL on an Intel 80486 can be
by-passed or disabled?

I want to single step using an externally controlled clock without the
PLL.

Thanks,
Wayne