  We present Auger-electron-detected magnetic resonance (AEDMR) experiments on
phosphorus donors in silicon, where the selective optical generation of
donor-bound excitons is used for the electrical detection of the electron spin
state. Because of the long dephasing times of the electron spins in
isotopically purified $^{28}$Si, weak microwave fields are sufficient, which
allow to realize broadband AEDMR in a commercial ESR resonator. Implementing
Auger-electron-detected ENDOR, we further demonstrate the optically-assisted
control of the nuclear spin under conditions where the hyperfine splitting is
not resolved in the optical spectrum. Compared to previous studies, this
significantly relaxes the requirements on the sample and the experimental
setup, e.g. with respect to strain, isotopic purity and temperature. We show
AEDMR of phosphorus donors in silicon with natural isotope composition, and
discuss the feasibility of ENDOR measurements also in this system.
