Hi
I am building a remote Capsense touch panel that will transmit very basic (5 Bytes) data to a 'Master' MCU that control switched devices that bring the system out out of sleep. The system needs to operate in a 12V automotive environment but on battery power for extended periods of time 6+ months.
Now, my initial thought was to use an Serial comms over RS485 to the MCU and as it will also need to be woken up this could be achieved with an RX interrupt. As I am a very much beginner with programming, my choices are based mainly on what I think I can implement and program. This topology, I thought was straight forward and simple enough to pull off with my limited abilities.
However, researching which driver to use I came across info around fail-safe termination and the possibility of the RX line falling into an unknown state thus triggering false interrupts when the bus is not used. That and the potential constant current current draw to maintain a high on USART Rx pin but also stay with in the levels of adequate RS485 termination voltages looked to be a PITA.
I looked around for other options. Which brings me here.
Is the above the 'best' most reliable and power efficient way to achieve what I want?
Would 'normal' RS485 termination be a better solution but implement an additional 485 channel solely for waking up the remote MCU via PinX INTs instead of a serial Rx ISR, be preferable?
Would a basic CAN driver with sleep and a wake-up pin be a better option at the MCU end? (will a CAN driver run with non CAN data and would this be low power as the driver can also go to sleep when not used - I like this option but have never used any form of CAN. I assume without the controller it's a normal differential line driver
Any other options I could consider (RF no chance - metal work)
Thanks