Any microprocessor with a digital I/O pin can be a bit-banging marvel if it has enough horsepower. Ubicom's SX chip is one such example. It has no peripherals. Instead, virtual peripherals are implemented via device drivers designed to exploit the controller's deterministic software implementation. Parallax now handles the SX and uses it as the basis for the company's Stamp product line.
Now, Ubicom has moved onto the IP3023 network processor. Although the IP3023 possesses a host of built-in peripherals, it retains the SX's software approach and augments it with a hardware scheduler that implements a zero-cycle context switch. The single-cycle, 250-MHz processor brings plenty of horsepower for higher-level peripherals using simple digital I/O like the SX or by augmenting built-in peripherals such as multiple Ethernet interfaces or high-speed serial controllers. The memory-to-memory architecture is designed to streamline the development of communications-oriented applications.
