Specifications
1.1.2 KA640 Firmware
Two
read-only memory (ROM) chips on
the
KA640 module contain
firmware. The firmware contains
three
major programs:
• A console program
• A
set
of
self-tests for
the
CPU
and
memory
• A
primary
bootstrap program
(VMB)
The console program receives control whenever
the
processor halts. For
the
KA640 CPU, a
halt
means
only
that
processor control
has
passed to
the
console program,
not
that
instruction execution stops. The
standard
VAX
console functionality is emulated
by
executing a program
in
ROM,
rather
than
by CPU microcode
or
a
separate
console processor.
Control passes to
the
firmware
under
any
of
the
following conditions:
• The system
is
powered
up
•
The
Reset
button
is pressed
•
The
Q22-bus BHALT signal is asserted (by pressing
the
Halt
button
or
by pressing
the
I
Break
I key when
the
Break
EnablelDisable switch is
set
to enable)
• A HALT instruction is executed
•
Halt
button
on
the
front control
panel
is pressed
• A system
error
occurs
At
Power-Up
At
power-up,
the
system
enters
one of
three
power-up modes
that
are
set
using
the
Power-Up Mode switch on
the
CPU cover panel. (The modes
and
their
meaning
are
described
later
in
this
chapter.)
The
console program
then
determines
the
console device type
and
console language.
The
console program
then
runs
the
self-tests for
the
CPU
and
memory. The
message
Performing
normal
system
tests.
is displayed on
the
terminal. As
the
tests
progress, a series of numbers
displays· on
the
console terminal. Operation . describes
the
power-on
sequence
and
shows examples
of
successful power-on operations. Micro VAX
Troubleshooting
and
Diagnostics describes possible problems
that
can
occur
during
power-on.
Base System Specifications
1-3