Motorola MVME162P-244 Series, Installation And Use Manual, Page: 67 / 146

Bringing up the Board
http://www.motorola.com/computer/literature 2-11
2
You can also execute the ROMboot function via the RB command,
assuming there is valid code in the memory devices (or optionally
elsewhere on the board or VMEbus) to support it. If ROMboot code is
installed, a user-written routine is given control (if the routine meets the
format requirements).
One use of ROMboot might be resetting the SYSFAIL
∗
line on an
unintelligent controller module. The NORB command disables the
function.
For a user’s ROMboot module to gain control through the ROMboot
linkage, four conditions must exist:
❏
Power has just been applied (but the ENV command can change this
to also respond to any reset).
❏
Your routine is located within the MVME162P4 Flash/PROM
memory map (but the ENV command can change this to any other
portion of the onboard memory, or even offboard VMEbus
memory).
❏
The ASCII string "BOOT" is found in the specified memory range.
❏
Your routine passes a checksum test, which ensures that this routine
was really intended to receive control at powerup.
For complete details on using the ROMboot function, refer to the
Debugging Package for Motorola 68K CISC CPUs User’s Manual.
Network Boot
Network Auto Boot is a software routine in the 162Bug Flash/EPROM
which provides a mechanism for booting an operating system using a
network (local Ethernet interface) as the boot device. The Network Auto
Boot routine automatically scans for controllers and devices in a specified
sequence until a valid bootable device containing boot media is found or
until the list is exhausted. If a valid bootable device is found, a boot from
that device is started. The controller scanning sequence goes from the
lowest controller Logical Unit Number (LUN) detected to the highest LUN
detected. (Refer to Appendix C for default LUNs.)