I,m working on a project which has an arduino pro mini as the main micro and it communicates with a SIM800 over serial.
It's a battery powered device, therefore I'm trying to save as much power as possible.
I have the option of using either HW serial interface or SW serial, I'd like to know which interface would be better suited for my needs.
Thanks.
On Pro Mini, the hardware serial is used for uploading your code and for debugging it with serial monitor. So you must use software serial for the sim800.
If you have an unused hardware serial port, you should always use it in preference to software serial, but with Pro Mini, you don't. Hardware serial can wake the atmega chip from a low power sleep mode when data is received, which might be helpful with battery circuits. If not using low power sleep modes, the power used by hardware serial and software serial is probably the same.
Thanks for your reply,
I was actually planning on adding some jumpers to my board which let me either program the board or use the serial for comm, so I could use hardware serial if needed.
I'm actually using low power sleep mode (power down), but it wakes up periodically and I don't really need it to wakeup on serial interrupt,
Do you think it would be worth it to use hw serial?
Whichever way you go, the battery will probably last longer than the 2G modem.
You will still be unable to use serial monitor for debugging purposes, which could make things much more difficult during development.
I don't think there will be any difference in power consumption between using hardware serial and software serial, so, no, I don't think it will be worth it.
To maximise battery life I would choose a 3.3V Arduino. You can buy boards based on atmega32u4 and samd21 which run at 3.3V and have spare hardware serial ports so that you can continue to use serial monitor for debugging.