RadiSys EPC-5A, Hardware & Software Reference Manual

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Chapter 5: Theory of Operation
Page 53
5 5
Video Controllers
The EPC-5A can operate with or without a video controller (such as the EXM-13B or
EXM-13A). The BIOS searches for an EXM having an EXM ID in the range
E8h-EFh (a range reserved for video controllers). The search is done by EXM slot
number, beginning at slot 0. If no EXM video adapter is found, the BIOS looks for a
PC add-in card video controller in an EXP-AM Adapter module. The error message
EXM CONFIGURATION ERROR
may appear if the video controller EXM or the EXP-AM
has not been configured via the setup screen.
In either case, the BIOS automatically initializes and uses the first one found.
If no video controller is present, the BIOS operates without one. Programs that use
the standard operating system and BIOS character output functions can be run
successfully (the output is ignored). However, programs that rely on specific video
modes, that write directly into the video RAM, or that directly call video BIOS
functions will fail.
Front Panel LEDs
The EPC-5A has five LEDs in the top left corner of the front panel. These LEDs are
described below:
RUN This LED is lit whenever the EPC-5A’s CPU is performing bus cycles.
It first comes on at power-up and should remain lit as long as the
system is running.
SYSFAIL This LED is only active when this EPC-5A is jumpered to be the
Slot-1 controller. It comes on whenever the system receives a
hardware reset and remains on until the initial power-on self-tests
have completed. It also comes on whenever the VMEbus SysFail line
is asserted.
TEST This LED is lit whenever the system is running its power-on
self-test. This only occurs during a hardware reset.
MASTER The Master LED is lit whenever the EPC-5A is accessing the
VMEbus.
SLAVE The Slave LED is lit whenever another master on the VMEbus is
accessing the EPC-5A’s memory.