Using an MCU like from MSP430 series, it is possible to create circuits that runs from battery power for years in some standby mode (waiting for button or realtime clock alarm for example).
However, if I for example add an OLED display, that has a specified 'sleep' power of 2mA, this wouldn't work.
How can I prevent the display consuming the battery power on standby? I first thought about switiching the display's GND by a MOSFET, but all other lines (data bus) may source current then, maybe the display even present VCC on the bus pins, if GND is disconnected? The display may source power from the bus pins then, draining the battery again or even destroying the MCU's outputs.
Is there a clean solution? Or do I have to find a display with equally low sleep consumption?