1747-ASB模块,A-B使用尺寸
在这条消息之后，有一个延迟，允许您如果愿意，可以中止自动启动过程。到在没有自动启动的情况下获得控制，您可以按断开键或软件中止或重置开关。
5.然后实际输入/输出开始：程序指向将指定介质的卷ID加载到RAM中，然后控制传递给它。
自动引导由ENV中包含的参数控制命令这些参数允许选择特定引导设备和文件，并允许启动延迟编程。参考有关更多详细信息，请参阅附录A中的ENV命令。
1747-ASB模块有两个备用EPROM插槽XU3和XU4可用于携带用户编程的EPROM。因此，您不必重新编程187Bug EPROM，以实现ROMboot功能。
ROMboot的一个用途可能是在非智能控制器模块。NORB命令禁用作用ROMboot序列
1.ROMboot在通电时配置/启用并执行（也可以在重置时）以两种方式之一：a、 通过环境（ENV）命令（请参阅附录A）b、 通过RB命令，假设EPROM（或可选模块上的其他位置或VMEbus）来支持它。
2.如果安装了ROMboot代码，则会给出一个用户编写的例程控制（如果例程满足格式要求）。用户的ROMboot模块通过ROMboot联动，必须满足四个要求：电源必须刚刚好应用更改此选项以响应任何重置。必须找到你的例行程序在MVME187 ROM内内存映射。将此更改为板载的任何其他部分内存，甚至非车载VMEbus内存。
ASCII字符串“BOOT”必须位于指定的内存范围内。您的例程必须通过校验和测试，这确保该例程真正打算在通电时接收控制。有关如何使用ROMboot的完整详细信息，请参阅
摩托罗拉88K RISC CPU调试包用户手册。
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.
ROMboot
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.
ROMboot Sequence
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). For a user's ROMboot module to gain control through the
ROMboot linkage, four requirements must be met: Power must have just been
applied.
Change this to respond to any reset.
Your routine must be located
within the MVME187 ROM
memory map.
Change this to any other portion of the onboard
memory, or even offboard VMEbus memory.
The ASCII string “BOOT” must be located within the specified memory range.
Your routine must pass a checksum test, which ensures that this routine was really
intended to receive control at powerupFor complete details on how to use ROMboot, refer to the
Debugging Package for Motorola 88K RISC CPUs User's Manual.
