I chose the BeagleBone Black (amongst other things) for the embedded microcontrollers (PRUs): Besides your usual ARM Cortex processor, you can put two “Programmable Real-time Units” to work. These are 2 RISC-cores clocked at 200MHz, optimised for real-time processing:
- Most instructions take 1 cycle (external memory access takes longer)
- No async interrupt handling, but provisions to efficiently check for pending interrupts
- Enhanced GPIO mode, that allows some pins to be directly controlled by the PRU, bypassing the normal GPIO-logic. This boosts performance down to 5ns latencies.
