Blackfin Bootloaders Here we document all of the ways you can boot the Blackfin processor. While there may be others, only the ones actively supported are documented here. Boot ROM - The Blackfin on-chip bootrom Das U-Boot - An extensible, portable, and configurable bootloader MicroMonitor - A free embedded system boot platform Overview Here is a general overview of how the typical Blackfin processor gets up and running. Power on processor in supervisor mode at level IVG5 If bypass, start executing at 0x20000000 (first async memory bank) If not bypass, start executing at 0xEF000000 (Boot ROM) Boot ROM executes check BMODE pins check OTP (One Time Programmable (memory)) memory (if available) configure selected boot source load LDR from source and execute the init section reprogram clocks initialize memory returns to Boot ROM load the rest of the application into external memory (if necessary) usually this is Das U-Boot could be MicroMonitor could be a standalone application could be the Linux kernel jump to the start of the application 2nd stage boot loader (Das U-Boot or MicroMonitor executes) perform any necessary relocation optional lower self to level IVG15 initialize devices/peripherals/etc… execute commands from environment setup environment load application load from anything the boot loader supports network SPI (Serial Peripheral Interface) Flash NOR (Not OR (parallel flash memory type)) Flash NAND (Not AND (large flash memory type)) Flash Hard Drive USB (Universal Serial Bus) Stick CD-ROM Drive serial (UART (universal asynchronous receiver/transmitter)) etc… get the application ready to run relocation decompression execute the application could be a stand alone (bare metal) application could be uC/OS (Operating System) could be a U-Boot application usually this is the Linux kernel, and then: Linux boots initialize devices/peripherals/etc… execute user space applications profit! Return to a higher level if application does not destroy the memory regions where U-Boot lives, it can return to U-Boot perform software system reset to get back to the Boot ROM