Bootloader for 328 with external 8MHz crystal

Using Arduino Microcontrollers
#1

Hello,

I'm using a 328p in a standalone configuration (5V, 16MHz crystal). Using Arduino as an ISP i was able to write the bootloader compiled from the latest optiboot sources. Everything seems OK and i can upload the sketches using a FTDI cable and the manual reset trick. Since i want to run it at 3.3V i changed the crystal with a 8Mhz one, i wrote without any error the corresponding bootloader (optiboot_atmega328_pro_8MHz.hex) and ... here start the problems: i can not upload any sketch. The entry from boards.txt of the 8MHz configuration is:

atmega328bb.name=ATmega328 w/ Optiboot (8 MHz Crystal)
atmega328bb.upload.protocol=arduino
atmega328bb.upload.maximum_size=32256
atmega328bb.upload.speed=115200
atmega328bb.bootloader.low_fuses=0xff
atmega328bb.bootloader.high_fuses=0xde
atmega328bb.bootloader.extended_fuses=0x05
atmega328bb.bootloader.path=optiboot
atmega328bb.bootloader.file=optiboot_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
atmega328bb.build.variant=standard

Is there any other bootloader for 328 running at 8MHz that i should try, or there is something wrong in my configuration?

Alin

#2

You could try burning the existing bootloader for an 8MHz 328: "LillyPad Arduino w/ ATmega328" If that works, your optiboot build might be the problem.

#3

Funny, I was just doing the same thing. I just selected the "Arduino Pro or Pro Mini (3.3V, 8 MHz) w/ ATmega328" board, and so burned the ATmegaBOOT_168_atmega328_pro_8MHz.hex bootloader, and all is well. (Using the 0022 IDE.)

Looks like I have a bad crystal or something though. Sketches run for a few minutes, then timing gets flaky. =(

OH! Try dropping the upload speed to 57600.

#4

[quote author=Jack Christensen link=topic=89988.msg676348#msg676348 date=1328240111] OH! Try dropping the upload speed to 57600. [/quote]

Thanks! Lowering the baud rate to 57600 in optiboot Makefile and in boards.txt made the bootloader working.

Alin

#5