Technical data

Alternate Boot Images and Safe Start MOTLoad Firmware
MVME3100 Single Board Computer Installation and Use (6806800G36A)
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The MVME3100’s IBCA needs to be mapped appropriately through the master’s VMEbus
bridge. For example, to use remote start using mailbox 0 on an MVME3100 installed in slot 5,
the master would need a mapping to support reads and writes of address 0x002ff348 in VME
CR/CSR space (0x280000 + 0x7f348).
3.7 Alternate Boot Images and Safe Start
Some later versions of MOTLoad support Alternate Boot Images and a Safe Start recovery
procedure. If Safe Start is available on the MVME3100, Alternate Boot Images are supported.
With Alternate Boot Image support, the bootloader code in the boot block examines the upper
8MB of the flash bank for Alternate Boot images. If an image is found, control is passed to the
image.
3.8 Firmware Startup Sequence Following Reset
The firmware startup sequence following reset of MOTLoad is to:
z Initialize cache, MMU, FPU, and other CPU internal items
z Initialize the memory controller
z Search the active flash bank, possibly interactively, for a valid POST image. If found, the
POST images executes. Once completed, the POST image returns and startup continues.
z Search the active flash bank, possibly interactively, for a valid USER boot image. If found,
the USER boot image executes. A return to the boot block code is not anticipated.
z If a valid USER boot image is not found, search the active flash bank, possibly interactively,
for a valid MCG boot image; anticipated to be upgrade of MCG firmware. If found, the image
is executed. A return to the boot block code is not anticipated.
z Execute the recovery image of the firmware in the boot block if no valid USER or MCG
image is found
During startup, interactive mode may be entered by either setting the Safe Start jumper/switch
or by sending an <ESC> to the console serial port within five seconds of the board reset. During
interactive mode, the user has the option to display locations at which valid boot images were
discovered, specify which discovered image is to be executed, or specify that the recovery
image in the boot block of the active Flash bank is to be executed.
3.9 Firmware Scan for Boot Image
The scan is performed by examining each 1MB boundary for a defined set of flags that identify
the image as being Power On Self Test (POST), USER, or MCG. MOTLoad is an MCG image.
POST is a user-developed Power On Self Test that would perform a set of diagnostics and then
return to the bootloader 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 MB or less in size; however, they must begin on
a 1MB boundary within the 8MB of the scanned flash bank. The Flash Bank Structure is shown
below: