Motorola MVME187 User Manual

Booting and Restarting 187Bug

4-7

4. Following this message there is a delay to allow you an 

opportunity to abort the Autoboot process if you wish. To 
gain control without Autoboot, you can press the 

BREAK

 key 

or the software 

ABORT

or 

RESET

 switches. 

5. Then the actual I/O begins: the program pointed to within 

the volume ID of the media specified is loaded into RAM and 
control passed to it. 

Autoboot is controlled by parameters contained in the ENV 
command. These parameters allow the selection of specific boot 
devices and files, and allow programming of the Boot delay. Refer 
to the ENV command in Appendix A for more details. 

There are two spare EPROM sockets, XU3 and XU4, available to 
carry user-programmed EPROMs. Therefore, you do not have to 
reprogram the 187Bug EPROMs in order to implement the 
ROMboot feature. 

One use of ROMboot might be resetting SYSFAIL* on an 
unintelligent controller module. The NORB command disables the 
function. 

1. ROMboot is configured/enabled and executed at powerup 

(optionally also at reset) in one of two ways:

a. By the Environment (ENV) command (refer to 

Appendix A)

b. By the RB command assuming there is valid code in the 

EPROMs (or optionally elsewhere on the module or 
VMEbus) to support it. 

2. If ROMboot code is installed, a user-written routine is given 

control (if the routine meets the format requirements).