At91rm9200 Booting

AT91RM9200 bootup

Boot Sequence:

• BMS Pin selects (AT91RM9200 Manual, 10.3.2.4, p.127)
  • high: internal ROM (see [below])
  • low: external 16bit non-volatile memory (see Manual)
• when using Internal ROM (AT91RM9200 Manual, 7. p.87)
  • Sequence:
  1. try to load and execute tiny program from SPI DataFlash
  2. try to load and execute tiny program from TWI EEPROM
  3. try to load and execute tiny program from from 8bit parallel non-volatile memory
  4. otherwise use "DBGU serial interface" and "USB Device Port" to let someone (Xmodem or DFU protocol) load and execute a tiny program.
  • tiny program means: program may be up to 12KByte (16K-4K) (AT91RM9200 Manual, 7.5, p.98)
  • the program is loaded into internal sram and immediately started there. (AT91RM9200 Manual, 7.1, p.87; 7.4, p.96)
  • (the program is started in a clean environment, i.e. as if the cpu just booted: the Internal ROM resets all peripherals before it executes the program. AT91RM9200 Manual, 7.3.3.3, p.93, Figure 7-6; 7.3.3.4, p.94, Figure 7-7; 7.3.3.5, p.95, Figure 7-8; 7.4, p.96)
  • the tiny program can be
    • a standalone application
    • part of a bigger application (mulit-stage bootloader)
  • types of tiny programs:

  1. a program to access non-volatile memory

  (for in circuit programming or firmware update; usually stored in nvm or uploaded via xmodem / DFU)

  2. a bootloader that gets its data from non-volatile memory

  (for automatically booting of bigger programs; usually stored in nvm)

  3. a bootloader that gets its data via xmodem / DFU

  (for manually booting of bigger programs; e.g.

  • for in circuit programming or firmware update in a second step or
  • for software development purposes)

  4. an other application

  • see also [mail about booting]
  • There are several tiny programs available: (find them via At91rm9200 Resources)
    • "RomBoot project for AT91RM9200DK v1.01"

    atmel bootloader - from atmel-application-note [1] [2]: [1-desc] [1-archive] [2-desc] [2-archive]

    ("Booting U-boot form Atmel Serial DataFlash on the AT91RM9200-DK Board")

    (see also At91rm9200 Resources: "Documentation" and "Target Software")

    type: 1. and 2. from above; compiler: ARM ADS 1.2 (ARM developer suite)

    as AN title says: for booting from (and accessing) spi dataflash

    [related email]

    • "RomBoot project for AT91RM9200DK v1.02"

    from [U-Boot on AT91RM9200-EK SPI Serial DataFlash] on at91.com

    [AT91RM9200-DataFlashBoot.zip (768KByte)]

    • gcc port of the "RomBoot project for AT91RM9200DK v1.01" (with minor non-port-related changes)

    [romboot.tar.gz (132KByte)]

    [related email]

    see ATMEL Romboot v1.01 ads vs gcc

    to compile this with the ecos-arm-gcc: add "-fno-builtin" to CFLAGS

    • [lomx.net lom-arm9-boot.tgz (6076KByte)] -> LOM-ARM9-Boot/loader/

    same as lomx.net CD lom-arm9.tgz -> arm/LOM-ARM9-Boot/loader/

    type: 3. from above; compiler: gcc

    maybe based on AT91RM9200BootV1.0.zip (see below)

    • Application Note "AT91RM9200DK U-Boot Flash Programming Solutions"

    type: probably 3. from above;

    • Application Note "AT91 Assembler Code Startup Sequence for C Code Applications Software"

    can be used as a basis for your own apps

    • Other Application Notes (see At91rm9200 Resources)
    • AT91RM9200-DK Software packages (see At91rm9200 Resources)
    • ATMEL AT91 CDROM: "ARM920T, ARM926EJ-S Based Products/AT91RM9200-DataFlashBoot.zip"

    similar to atmel bootloader above ?

    • ATMEL AT91 CDROM: "ARM920T, ARM926EJ-S Based Products/AT91RM9200_BOOTROM_Code/AT91RM9200BootV1.0.zip"
    • u-boot: Bootloader

    this bootloader is bigger than a tiny program, but it can be started via a tiny program

u-boot:

• general:
  • [U-Boot project homepage]
  • [The DENX U-Boot and Linux Guide (a)]
  • [The DENX U-Boot and Linux Guide (b)]
• for at91rm9200:
  • [Forum: primary boostrap, U-boot and at91rm9200]
  • [Forum: U-boot and AT91RM9200]
  • Application Note "AT91RM9200DK U-Boot Flash Programming Solutions" (includes u-boot patch)
  • AT91 CDROM: [UBoot/AT91RM9200-Boot.tgz]

redboot:

• see At91rm9200 Drivers and Ecos At91rm9200