Performance analysis of embedded firmware for the detection of gamma-ray bursts on a 2U CubeSat

The Gamma-Ray Module on EIRSAT-1 is a <1U CubeSat compatible instrument for the detection of high energy transient events, primarily intended for low earth orbit detection of gamma-ray bursts. The compact and low power nature of the design makes GMOD a novel instrument for GRB detection on a 2U CubeSat. The GMOD motherboard provides support to the instrument by managing a number of operation critical duties, most importantly the reliable execution of the experiment, temporary onboard flash storage and transfer of time tagged event readout to the EIRSAT-1 on-board computer. Executing these tasks is the TI MSP430FR5994 microcontroller which is loaded with a custom firmware developed for the instrument motherboard. A recent investigation into the firmware performance at fixed trigger rates proved that the firmware concept was viable for reliable detector readout. We present an investigation carried out to further quantify the performance of the firmware in a more realistic operational mode. These tests accurately simulate the rates expected by GMOD during detection of GRBs and measure performance by comparing the expected output to the actual instrument output. This is done by externally triggering the detector readout to mimic the expected rates for a range of GRB profiles and expected fluxes derived from the 4th Fermi GBM catalogue. This work evaluates the flight model firmware performance for a sample of 40 GRBs spanning a range of peak fluxes and durations.