Differences

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--- arduino:arduino_without_a_bootloader [2020/02/27 18:13] – [Blessed is the bootloader] mithat
+++ arduino:arduino_without_a_bootloader [2020/02/27 18:18] – [Cursed is the bootloader] mithat
@@ Line 12: / Line 12: @@
 ===== Cursed is the bootloader =====
-There are times when you might want to bypass the convenience a bootloader offers and program your microcontroller directly. The most common reason is that you want to be able to use //all// of the available flash storage for your program. Bootloaders in ATmega chips are stored in the same flash memory as "user programs." While the amount of required memory is small---for example, the [[https://github.com/Optiboot/optiboot|Optiboot]] bootloader used in common Arduinos is a mere 512 bytes---sometimes you just need to use every last byte of flash on the micro for your program.
+In spite of the convenience a bootloader offers, there are times when you might want to forego this and program a microcontroller directly. The most common reason is that you want to be able to use //all// of the available flash storage for your program. Bootloaders in ATmega chips are stored in the same flash memory as "user programs." While the amount of required memory is small---for example, the [[https://github.com/Optiboot/optiboot|Optiboot]] bootloader used in common Arduinos is a mere 512 bytes---sometimes you just need to use every last byte of flash on the micro for your program.
-Another reason to not use a bootloader is that your project's startup time is critical. The Arduino bootloader introduces about a second and a half delay between power-up/reset and running your program. Without a bootloader, your code starts running almost instantaneously.
+Another reason to not use a bootloader is that the startup time is critical. The Arduino bootloader introduces about a second and a half delay between power-up/reset and running your program. Without the bootloader, your code starts running almost instantaneously.
 Yet another situation where you might not want a bootloader is if you have lowered or disabled the [[https://microchipdeveloper.com/8avr:bod|Brown-Out Detection]] so you can use every last ounce of battery juice in a portable application.((Disabling brown-out detection or lowering the threshold of detection involves [[arduino:atmega328p_arduinos_and_custom_fuse_settings|custom fuse settings]] and is beyond the scope of this article.)) Without brown-out detection, the erratic system behavior you can expect at very low voltages could cause a program jump to an arbitrary part of the code in flash storage. If you use a bootloader, this could be a jump into bootloader code. This then has the potential to start a cascade of events that leads to the bootloader overwriting your program code. If you're not using a bootloader, the code you have programmed can't be corrupted this way.((Not using a bootloader in this situation will keep the program memory form becoming corrupted, but EEPROM and other things can still be battered when the voltage falls below the minimum for a given clock frequency. The risks are described more completely in the [[http://ww1.microchip.com/downloads/en/Appnotes/doc1051.pdf|AVR180: External Brown-out Protection]] application note.))