 They include up to 4096 12-bit words of Flash memory and up to 262 bytes of random-access memory (RAM), an eight bit counter and other support logic.They are especially geared toward the emulation of I/O hardware in software, which makes them very flexible.While Parallax's SX micros are limited in variety, their high speed and additional resources allow programmers to create 'virtual devices', including complete video controllers, as required.