Hi,.....
i am developing a product. The same requires Hot redundancy of the two microcontrollers. The input & Outputs will be comman for both controllers. HMI & keyboard will be comman for the both. The failure of one controller shall be taken care by another. Is it possible to do the same. If any other option is available please suggest.
Yes, it can be "easily" done as long you plan your logic and circuitry hardware. It will get fairly complex. I know this because I have used two microcontrollers each of which calling a function from one another using serial uart. only problem with serial uart you can only use two devices on the same uart bus.
I'm sure you can find some methods if you need more than two microcontroller network, and you don't need to use CAN protocol since CAN protocols require modules for each microcontroller. I know I2C has multi-master libraries.
I think this is probably redundant after 9 years!