Hi guys, i am building a custom arduino compatible board, and i'm using the atmega328p-Au chip.
I am powering the board with a 3.7 lipo battery, and i was wondering if i could still use the 16 mhz external oscillator even if the chip will be powered with 3.3v (i'll use a voltage regulator).
Second question:
How am i suppose to burn the bootloader and upload sketches into the chip? I should make ICSP or FTDI headers? Which one will be able to burn bootloader and upload sketches? Thanks!
I believe the maximum speed at 3.3V is 8 Mhz.
As stated above the device is rated for 8 MHz at 3.3v but you will probably find that it will work at 16 MHz. I wouldn't recommend doing that for a commercial design but I know that the Moteino devices that I bought are working fine under those conditions.
You will need the ICSP connections to burn the bootloader. You can use either the ICSP or the FTDI connections to upload sketches.
Don
Ok, now it's more clear, thank you.
But can i still use the Arduino IDE to upload sketches though the ICSP?
How am i suppose to burn the bootloader and upload sketches into the chip? I should make ICSP or FTDI headers? Which one will be able to burn bootloader and upload sketches? Thanks!
I use an FTDI Basic from Sparkfun to load sketches in my ATmega328-PU .
without it,
Not according to spec sheet. You can safely go up to about 13MHz with 3.3V supply. 16MHz will be overclocking.
That would explain why they seem to be pretty successful running at 16 Mhz. It's a relatively small amount of overclocking.
Don
Maybe enough cooling will help the overclocking.
Maybe small - not all functionality is guaranteed to work when underpowered & over clocked.
Serial functionality usually takes a hit, has been reported here before.