Atmega328-PU speed

Other Hardware 3rd Party Boards
1

Hi everyone!

I have an issue with my atmega328-PU; I've changed the signature in "avrdude.config" file to program the MCU using arduino IDE, I've choosed Aduino UNO as a board, and when I uploaded the Blink sketch to the atmega328-PU the blinking speed is more slow than what I suspected.

I tried the sketch with and without the 16Mhz crystal. But the blink still too slow.

Any idea :astonished:

here the boards.txt file :

# See: http://code.google.com/p/arduino/wiki/Platforms

##############################################################

uno.name=Arduino Uno
uno.upload.protocol=arduino
uno.upload.maximum_size=32256
uno.upload.speed=115200
uno.bootloader.low_fuses=0xff
uno.bootloader.high_fuses=0xde
uno.bootloader.extended_fuses=0x05
uno.bootloader.path=optiboot
uno.bootloader.file=optiboot_atmega328.hex
uno.bootloader.unlock_bits=0x3F
uno.bootloader.lock_bits=0x0F
uno.build.mcu=atmega328p
uno.build.f_cpu=16000000L
uno.build.core=arduino
uno.build.variant=standard

the boards.txt in the arduino sketchbook :

##############################################################

atmega328bb.name=ATmega328 on a breadboard (8 MHz internal clock)

atmega328bb.upload.protocol=stk500
atmega328bb.upload.maximum_size=30720
atmega328bb.upload.speed=57600

atmega328bb.bootloader.low_fuses=0xE2
atmega328bb.bootloader.high_fuses=0xDA
atmega328bb.bootloader.extended_fuses=0x05
atmega328bb.bootloader.path=arduino:atmega
atmega328bb.bootloader.file=ATmegaBOOT_168_atmega328_pro_8MHz.hex
atmega328bb.bootloader.unlock_bits=0x3F
atmega328bb.bootloader.lock_bits=0x0F

atmega328bb.build.mcu=atmega328p
atmega328bb.build.f_cpu=8000000L
atmega328bb.build.core=arduino:arduino
atmega328bb.build.variant=arduino:standard

And the part I've changed on avrdude.config :

 signature = 0x1e 0x95 0x14;
2

There must be a zillion Forum posts about this topic:
HERE

3

Thanks mrburnette but it does'nt resolve my problem,

I've an issue with the speed off the MCU not the MCU programming I think :roll_eyes:

4

mohsine2010:
Thanks mrburnette but it does'nt resolve my problem,

I've an issue with the speed off the MCU not the MCU programming I think :roll_eyes:

A chip's digital signature does not affect the clock speed ... Crystal freq and AVR fuses set the boot-up speed.
Here is the fuse info

AVRDUDE just uses the signature to prevent accidental flashing the wrong chip model.. A failsafe that is far too much toouble.

Ray

5

Is it half the expected blink speed? You uploaded using the wrong board option.

Is it 1/8th the expected blink speed? You didn't set the fuses - it's still dividing clock by 8.

Is it 1/16th the expected blink speed? You did both.

6

@mohsine2010,
You don't mention burning the bootloader using a programmer - in the IDE that is what burns the fuses with the settings to use the external crystal as the clock source.