yes right,


task switching may be a problem in 51s. look over the i386 architechture and its complexity, which is specialy design for multi tasking and it has hardware task switching support. why? if it would have possible efficiently by software.

here we have sipmle small powerful embedded controller which is intended to use for small control aplication where small ammount of resources are there. minimum context switching requires IP,SP,PSW etc are to be saved and restoration of above for new process. this assumes other process destryes nothing other than these. state machine can be powerfully used as michael suggests. i think one shoul avoid this multitasking in microCs. To generate paralelism multiprocessors also can be used.

if degree of multi programming increase so that quantum (time sharing is assumed) < context switch time is greater than a quantum MCU will only switch wont do any thing at all.


abhishek