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MOTLoad Firmware
MVME3100 Single Board Computer Installation and Use (6806800M28C)
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3.10.6 Boot Image Firmware Scan
The scan is performed by examining each 1 MB boundary for a defined set of flags that identify
the image as being POST, USER, or Alternate MOTLoad. POST is a user-developed Power On Self
Test that would perform a set of diagnostics and then return to the boot loader image. USER
would be a boot image, such as the VxWorks bootrom, which would perform board
initialization. A bootable VxWorks kernel would also be a USER image. Boot images are not
restricted to being 1 MB or less in size; however, they must begin on a 1 MB boundary within
the 8 MB of the scanned flash bank. The flash bank structure is shown below:
The scan is performed downwards beginning at the location of the first possible alternate
image and searches first for POST, then USER, and finally Alternate MOTLoad images. In the
case of multiple images of the same type, control is passed to the first image encountered in
the scan.
Safe Start, whether invoked by hitting ESC on the console within the first five seconds following
power-on reset or by setting the Safe Start jumper, interrupts the scan process. The user may
then display the available boot images and select the desired image. The feature is provided to
enable recovery in cases when the programmed Alternate Boot Image is no longer desired. The
following output is an example of an interactive Safe Start:
ABCDEInteractive Boot Mode Entered
boot> ?
Interactive boot commands:
'd':show directory of alternate boot images
'c':continue with normal startup
'q':quit without executing any alternate boot image
'r [address]':execute specified (or default) alternate image
'p [address]':execute specified (or default) POST image
'?':this help screen
Address Usage
0xFFF00000 to 0xFFFFFFFF Boot block. Recovery code.
0xFFE00000 to 0XFFFFFFFF Backup MOTLoad image
0xFFD00000 to 0xFFDFFFFF First possible alternate image
0xFFC00000 to 0xFFCFFFFF Second possible alternate image
.... Alternate boot images
0xFF899999 to 0xFF8FFFFF Bottom of flash (flash size varies per product)