Redboot resource usage, Flash resources – Comtrol eCos User Manual

Page 108

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Chapter 1. Getting Started with RedBoot

The chosen mode has influence on flash and RAM resource usage (see

the Section called RedBoot Resource Usage

)

and the procedure of an in situ update of RedBoot in flash (see

Chapter 4

).

The startup mode is controlled by the option CYG_HAL_STARTUP which resides in the platform HAL. Some
platforms provide only some of the RAM, ROM, and ROMRAM modes, others provide additional modes.

To see mode of a currently executing RedBoot, issue the version command, which prints the RedBoot banner,
including the startup mode (here ROM):

RedBoot>version

RedBoot(tm) bootstrap and debug environment [ROM]

Non-certified release, version UNKNOWN - built 13:31:57, May 17 2002

RedBoot Resource Usage

RedBoot takes up both flash and RAM resources depending on its startup mode and number of enabled features.
There are also other resources used by RedBoot, such as timers. Platform-specific resources used by RedBoot are
listed in the platform specific parts of this manual.

Both flash and RAM resources used by RedBoot depend to some degree on the features enabled in the RedBoot
configuration. It is possible to reduce in particular the RAM resources used by RedBoot by removing features
that are not needed. Flash resources can also be reduced, but due to the granularity of the flash (the block sizes),
reductions in feature size do not always result in flash resource savings.

Flash Resources

On many platforms, a ROM mode RedBoot image resides in the first flash sectors, working as the board’s primary
boot monitor. On these platforms, it is also normal to reserve a similar amount of flash for a secondary RAM mode
image, which is used when updating the primary ROM mode image.

On other platforms, a ROMRAM mode RedBoot image is used as the primary boot monitor. On these platforms
there is not normally reserved space for a RAM mode RedBoot image, since the ROMRAM mode RedBoot is
capable of updating the primary boot monitor image.

Most platforms also contain a FIS directory (keeping track of available flash space) and a RedBoot config block
(containing RedBoot board configuration data).

To see the amount of reserved flash memory, run the fis list command:

RedBoot> fis list

Name

FLASH addr

Mem addr

Length

Entry point

RedBoot

0x00000000

0x00000000

0x00020000

0x00000000

RedBoot[RAM]

0x00020000

0x06020000

0x00020000

0x060213C0

RedBoot config

0x0007F000

0x0007F000

0x00001000

0x00000000

FIS directory

0x00070000

0x00070000

0x0000F000

0x00000000

4

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