Print Page - Using a crystal instead of resonator

Title: Using a crystal instead of resonator
Post by: kobuki on May 23, 2017, 07:03:12 PM

I want to use a 16.000 MHz crystal in place of the resonator for my project. I would like to find out what fuses to use. Chip is the 328p.

Original Moteino fuses (low, high, ext): 0xDE, 0xDC, 0x05 - for the clock source it means an "Ext. Crystal Osc.; Frequency 8.0- MHz; Start-up time PWRDWN/RESET: 258 CK/14 CK + 65 ms; [CKSEL=1110 SUT=01]"

16 MHz/5V Uno uses: 0xFF, 0xDE, 0x05 - "Ext. Crystal Osc.; Frequency 8.0- MHz; Start-up time PWRDWN/RESET: 16K CK/14 CK + 65 ms; [CKSEL=1111 SUT=11]"

The difference is the startup delay: 258 CK in the case of the Moteino and 16K CK in case of the Uno. Should I use the latter? Can I just leave the values meant for the original Moteino for the crystal? I guess this is important for the stable startup of the chip. Maybe the Uno value is just a safe one?

Any hints for setting the clock source fuses?

Title: Re: Using a crystal instead of resonator
Post by: Felix on May 24, 2017, 07:57:36 AM

I think you can keep all the same fuses.

Title: Re: Using a crystal instead of resonator
Post by: kobuki on May 24, 2017, 07:59:24 AM

OK, will try that, thanks.

LowPowerLab Forum

Hardware support => Moteino => Topic started by: kobuki on May 23, 2017, 07:03:12 PM