  We present an analysis of the X-ray variability properties of the NLS1 galaxy
Ton S180, based upon a 12-day continuous ASCA observation. We observe flux
variations of a factor of 3.5 in the 0.7-1.3 keV band and 3.9 in the 2-10 keV
band.Time-resolved spectroscopy (~1d sampling) reveals that the broad `soft
hump' component at energies <2 keV shows flux variations on timescales down to
1 day that are well correlated with the photon index and the 2-10 keV band
flux. A broad Fe K$\alpha$ emission is detected. There is a evidence for a
narrow Fe K$\alpha$ line at ~6.8 keV, indicating an origin in ionized material.
We do not detect significant variations of the line flux or EW on ~1 day-1 week
timescales. The softness ratio reveals spectral variability on timescales down
to ~1000 s, indicating that the power-law continuum and soft hump fluxes are
not well correlated on this timescale. It also shows a slow decline across the
observation, due to a combination of the different time-variability of the
power-law continuum and soft hump flux on timescales of ~1 week. The X-ray
emission originates within 12 Schwarzschild radii, and the amplitudes and
timescales of the rapid variations we observed are consistent with those
expected within disk-corona models. The soft hump variability timescale rules
out an origin in large scale components (circumnuclear starburst). The
$\Gamma$-soft hump correlation is consistent with the soft hump being produced
by up-scattering of the accretion disk radiation within a flaring disk corona.
