Hi, I've searched a ton of schematics on the web trying to figure out how to power on smd atmega328p-au but can't find what I'm looking for. I refuse to believe that the reset pin and aref pin are required to power on the chip but if I'm wrong I can work with it still. I know a 16.00 crystal and 22pf capacitors are absolutely required like its 8pin DIP version. So getting to the point, can I just power it on with the crystal and capacitors and just the VCC and GND pins?
Or are aref and reset pin required to power it on with a battery as well?
If you check the datasheet, you'll see the ATmega328P is not rated to run at 16 MHz when powered at 3.7 V. You can run it at a lower clock speed, boost the 3.7 V, or run it out of spec and hope for the best.
Zackypoo:
I know a 16.00 crystal and 22pf capacitors are absolutely required
They are not absolutely required. The ATmega328P can be run off the internal oscillator. It is less accurate but plenty good enough for many applications.
Thanks! But can I run it off just the gnd and vcc pins or is the aref pin and reset pin required? The chip has already been programmed and I only have two pins that need to connect to ground for it to do what I need it to do. Just looking for what pins of the chip to connect to the battery to just power the smd chip on.
Depends on the fuse settings you used to program it...
Reset => If reset is disabled you can leave it floating, otherwise you have to pull it to Vcc
crystal => If it's configured to run of the internal oscilator you don't need an external. Otherwise you need an external with the correct frequency (determined by the program). And indeed note 16MHz isn't in spec at 3,7V.
aref doesn't need to be connected as far as I know.
Reset does have an internal pull-up so an external pull-up is not absolutely required. However, it's a weak pull-up so if there is a lot of EMI you could end up with mysterious resets. That extra resistor could save you a lot of headache in the long run.
pert one more question (for pert) What ohm resistor would you recommend for stopping an interference? And would it connect from reset to Vcc or reset to ground? Apologize if it sounds silly still getting used to this stuff.
10K is the most common value. That's what Arduino uses on their boards. That's a reasonably strong pull-up. It would take very strong interference to overcome that. You connect it from reset to Vcc to keep the pin high until it's intentionally pulled low. When the reset pin is pulled low, it resets the microcontroller.