RS-232 Transceiver wake up MCU

[binaryninja]

Hi, I am trying to find a scheme that will wake up the microcontroller when the serial transceiver receives a signal.

What pins could I use on a transceiver that will allow me to do this? I was thinking about using the charge pump V+ or V- somehow, since these are active when the transceiver starts transmitting.

Any ideas?

Thanks!

 

[dcoder]

What about using signal from TX pin on tranceiver? You can connect TX to external interrupt pin on MCU. Falling edge on TX will generate an interrupt, which waked up MCU.

 

[andre_luis]

The sugestion from dcoder is usefull.
However depending on wich microcontroller you´re using it may have built-in that funcionality enabled by any Special Function Register.

+++

 

[microlab]

hi

there are many possible ways to do the same
before that, which MCU you are using?

ml

 

[ctownsend]

just use the uart interrupt in the mcu

 

[ZASto]

just use the uart interrupt in the mcu

and assume that the first byte will be garbage. In your implement sending the first byte (ex. 10101010 (0xAA) or 01010101 (0x55)) just for waking up your uC.