User`s manual

ROMboot

1-16

established that the routine was meant to be used for

ROMboot.

Under control of the ENV command, the sequence of searches is as

follows:

1. Search direct address for ÒBOOTÓ. The direct address points

to an installed ROMboot routine. It is a variable that may be

set using the ENV command.

2. Search complete ROM map.

3. Search local RAM, at all 8KB boundaries starting at the

beginning of local RAM.

4. Search the VMEbus map (if so selected by the ENV

command) on all 8KB boundaries starting at the end of the

onboard RAM. VMEbus address space is searched both

below (if the start address of local RAM is not located at 0)

and above local RAM up to the beginning of FLASH Space.

Sample ROMboot Routine

The example ROMboot routine performs the following:

❏ Outputs a <CR> <LF> sequence to the default output port.

❏ Displays the date and time from the current cursor position.

❏ Outputs two more <CR> <LF> sequences to the default

output port.

❏ Returns control to PPCBug.