Hi, I tried to upgrade my breadboard arduino, and ended up ordering some Atmega328-PU instead of Atmega328P-PU chips. I could burn the bootloader to them by modifying the avrdude.conf file with no problem, but the problem I'm facing is, the chips aren't working with any bootloader other than the Uno optiboot.
I've tried the bootloaders for Atmega328 versions of Duemilanove, Nano and Pro and with each of them, the Pin 13 LED just keep giving short blinks every 1.5 seconds and nothing else happens. I've read somewhere in this forum that this happened to someone who apparently overflown the memory with a sketch which changed the watchdog timer settings. He solved it by re-flashing the bootloader, but in my case, the bootloader is causing the problem.
I've tried the Uno bootloader and it works fine, or at least the Pin 13 LED doesn't blink continuously. With optiboot, it blinks fast 3 times and then stops. But still, I can't use the optiboot because my 16MHz crystals are very cheap and cannot provide the accuracy required to support UART at baudrate 115200. I've once tried by recompiling optiboot with baudrate 57600 and it worked very well.
I'm using USBasp to burn the bootloader and a USB-Serial TTL converter based on the VUSB protocol.
Thanks for any Reply.