Comtrol eCos - Manual (Page 217)

Chapter 5. Installation and Testing
NOTE: the BSE firmware runs its serial IO at 9600 Baud; RedBoot runs instead at 38400 Baud. You must
select the right baud rate in your terminal program to be able to set up the BSE firmware.
After a reset, the BSE firmware will print
Boot: BSE 2000 Sep 12 2000 14:00:30
autoboot: "go 40000" [hit ESC to abort]
and then RedBoot starts, switching to 38400 Baud.
Once you have installed a bootable RedBoot in the system in this manner, we advise re-installing using the generic
method described in
Chapter 4 in order that the Flash Image System contains an appropriate description of the flash
entries.
Cohabiting with POST in Flash
The configuration file named redboot_POST.ecm configures RedBoot to build for execution at address
0x50040000 (or, during bootup, 0x00040000). This is to allow power-on self-test (POST) code or immutable
firmware to live in the lower addresses of the flash and to run before RedBoot gets control. The assumption is that
RedBoot will be entered at its base address in physical memory, that is 0x00040000.
Alternatively, for testing, you can call it in an already running system by using go 0x50040040 at another Red-
Boot prompt, or a branch to that address. The address is where the reset vector points. It is reported by RedBoot’s
load command and listed by the fis list command, amongst other places.
Using the POST configuration enables a normal config option which causes linking and initialization against mem-
ory layout files called "...post..." rather than "...rom..." or "...ram..." in the
include/pkgconf directory. Specifi-
cally:
include/pkgconf/mlt_arm_sa11x0_nano_post.h
include/pkgconf/mlt_arm_sa11x0_nano_post.ldi
include/pkgconf/mlt_arm_sa11x0_nano_post.mlt
It is these you should edit if you wish to move the execution address from 0x50040000 in the POST configuration.
Startup mode naturally remains ROM in this configuration.
Because the nanoEngine contains immutable boot firmware at the start of flash, RedBoot for this target is configured
to reserve that area in the Flash Image System, and to create by default an entry for the POST mode RedBoot.
RedBoot> fis list
Name FLASH addr Mem addr Length Entry point
(reserved) 0x50000000 0x50000000 0x00040000 0x00000000
RedBoot[post] 0x50040000 0x00100000 0x00020000 0x50040040
RedBoot config 0x503E0000 0x503E0000 0x00010000 0x00000000
FIS directory 0x503F0000 0x503F0000 0x00010000 0x00000000
RedBoot>
The entry "(reserved)" ensures that the FIS cannot attempt to overwrite the BSE firmware, thus ensuring that the
board remains bootable and recoverable even after installing a broken RedBoot image.
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