A Review of RTOS Fundamentals
摘要
Traditional embedded systems were stand-alone systems that were not extensively networked to other systems. Communication, when present, typically, was over a simple communications serial link such as RS232, or HART. HART [1] is an industrial protocol that can communicate over legacy 4–20 mA analog instrumentation current loops, but these days there is also a wireless version of HART and there are HART modems that can be used to run HART over RS232. Later specialized serial communications such as SPI and I2C were developed for communicating with small specialized devices such as, for example: