Hello, I'm planning to use this board to read the speedometer and rpm guage and am wondering, how long does it take for the board to boot up? I usually start to drive the car after starting it (without warming up first).
If you use the bootloader, it takes some seconds, if you go without the bootloader and burn the program straight to the chip, there's almost no booting time.
Thanks for the info
quick question on the topic - i am still fuzzy about bootloaders... are you saying that the bootloader is what allows you to reflash the chip with new code, while no bootloader = one chip, one code forever ?
A bootloader takes advantage of the self-programming capabilities of the AVR family, but not having a bootloader doesn't mean that with a separate programmer you can't reprogram the chip.
The bootloader sits in a protected area of flash memory, and can overwrite the rest of the unprotected flash.
So basically bootloader makes it easier to reprogram the chip?
Yes, in the case of the Arduino it does exactly that.
But using specific hardware programmers you can reprogram the atmega168 many times also, with the additional benefit of having 2k more space for the program.
Arduino proved though, that the bootloader, the USB to serial chip, the nice set of libraries and the IDE all combined are a winning combination. So the bootloader is THE way to an Arduino is reprogrammed. When the chip starts the bootloader is the first program to run. If data is coming the serial line the bootloader assumes that this data is a new program and stores it on the chip beginning at a specific addres. If no data is comming, then the bootloader is looking if at that specific address there is a program already, and if so - runs it.