  Fast electronic readout for high-channel density scintillator-based systems
is needed for radiation tracking and imaging in a wide range of applications,
including nuclear physics, nuclear security and nonproliferation. Programmable
electronics, like FPGAs and ASICs, provide a fast way of conditioning and
processing the signal in real time. In this paper, we present a pulse shape
discrimination (PSD) method based on the shaping circuit of a commercially
available ASIC, the Citiroc1A by CAEN Technologies. We used two different
shaping times per detector channel to calculate a shaping parameter that
enables PSD. Using our new method, neutron and gamma-ray pulses detected by a
d$_{12}$-stilbene scintillator can be effectively discriminated at light output
values greater than 0.15 MeVee. While not achieving the PSD performance of
traditional offline charge integration, our method does not require the
transfer of data to a separate system for further processing and enables the
direct deployment of high-channel density multi-particle detection systems.
Moreover, the availability of a wider range of shaping times than those on the
Citiroc1A can potentially further improve the PSD performance.
