I have a "special" need
I just receive and tried and ITEAD808 module
I connect from ITEAD808
Rx to TX of Mini pro
Tx to Rx of Mini pro
PWD to pin 5 of Arduino (2sec of pulse to power the ITEAD module)
VIO (input) to VCC
DTR to 13
Ri to 6
and BAT to the RAW pin of Arduino
BAT pin is a pin connected to the Li Battery and give a power of 3.7V
ITEAD808 has a power press button the switch of/on the module which is an hard power (=to PWD)
The battery is loaded because of the USB port, so the battery should remind connected as it is.My problem
I would like to have one switch to power on/off Mini pro AND ITEAD808. If I press the ITEAD power button, it does not turn off the Arduino because it's connected to the BAT pin. I can not have a switch between the BAT and the RAW pin because it will not switch the ITEAD.My question
If I unconnect the VIO pin the ITEAD Rx and Tx are unactive. I suppose, if I press to ITEAD power button two sec to power it off, the ITEAD Rx and Tx are unactive.
The how can I "listen" Rx and TX to know if RX and TX are active or not.
IF there are not active, I can create a switch wich a transistor to unconnect the BAT/RAW link to unpower the system.
Do you have a better idea?