Not everything has to be asynchronous. For example, if your real-time system has to respond in less than 1ms, all you have to do is design a system able to resp

Not everything has to be asynchronous. For example, if your real-time system has to respond in less than 1ms, all you have to do is design a system able to respond in less than 1ms. If your system has to respond in exactly 1ms, you take the previous system (the one able to respond in less than 1ms) and use a 1ms clock/timer/monostable to delay it.