Wrong frequency somehow

Projects Programming
1

Hi all

I have a PCB I made with an ATmega328p onboard (TQFN I think is the footprint? - can never remember).
Added a 16mhz crystal with a pair of 22pf caps pulling the lines to ground... usual layout.

Programming it using an USBASP over SPI to program it. That all works fine.

But, using Pro Mini as I usually do in the Arduino IDE, with 328p 5v 16Mhz selected, the blink test routine is running VERY slowly.

Instead of blinking the led once a second, it's about once every 14 seconds.

Changed the crystal to a new 16Mhz, still the same, so not sure what I check next? It uploads code fine, just runs biblically slow.

2

Most likely, the divide by 8 fuse (CKDIV8) is still set. They come that way from the manufacturer, as documented in the data sheet.

3

:roll_eyes: Oh that sounds like fun....

Google time. Thanks!

4

Oh.... select UNO, press flash bootloader. Done

Thanks jremington

5

If you are going to be programming via ISP, and don't need the bootloader, MCUdude's Minicore has a no-bootloader option. May seem contradictory, but you still need to flash the bootloader with the no-bootloader setting in order to set the fuses correctly.

6

Does this free up any memory/space?

7

Using the no-bootloader option frees up the flash memory allocated for the bootloader (512 bytes on an UNO).

8

Is the problem with CPU Freq solved?

9

Yes problem solved. Thank you

10

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