Intel MCS48 User Manual page 424

INTELLEC
PROMPT
48
FEATURES
Single
Component Computer
The
8748
is
the
first
microcomputer
fully integrated
on
one component.
All
elements
of a
computing system
are
provided, including CPU,
RAM,
I/O,
timer, interrupts,
and
erasable,
reprogrammable
nonvolatile
program memory.
Programming
Socket
PROMPT'S
programming
socket programs
this revolu-
tionary "smart
PROM"
—
the
8748
—
in
a
highly
reliable,
convenient manner.
A
fail-safe interlock en-
sures the device
is
properly inserted before applying
programming
pulses.
Each
location
may
be
individually
programmed, one
byte
at
a
time.
A
read-bef ore-write
programming
algorithm prevents device
damage
by
in-
advertently
programming
unerased
memory.
MCS-48
Processors
The
execution socket accepts
either
an 8035
or
an 8748
MCS-48
processor.
Both
are supplied with
each
PROMPT
48,
and
either
can
serve
as
heart of the
PROMPT
system. There
are
no processors
within the
PROMPT
48 mainframe, which
instead contains monitor
ROM
and
RAM,
user
RAM,
peripherals,
drivers,
and
sophisticated
control
circuitry.
Once
a processor
is
seated
in
the execution socket and power
is
applied, the
PROMPT
system comes
to
life.
Various
access modes
may
be
selected
such
as
program
execution from
PROMPT
system
RAM,
or
from
on-chip
PROM.
Thus
pro-
grams
may
first
be executed from
PROMPT RAM
with
the 8035
processor.
When
debugging
is
complete, the
8035 (execution socket) processor can
program
the
8748
(programming
socket)
processor.
Finally,
a
pro-
grammed
8748 processor may
be exercised by
itself
from
the execution
socket.
The
execution socket
pro-
cessor runs
either monitor
or user
programs.
System
Monitor
The system
reset
command
initializes
the
PROMPT
system and
enters the monitor. The monitor
interrupt
command
exits
a user program
gracefully,
preserving
system
status
and
entering the monitor.
The
user
inter-
rupt
command
causes an
interrupt
only
if
the
PROMPT
system
is
running a
user program.
A
comprehensive
system
monitor
resides
in
four
1K-byte read only
memories.
It
drives the
PROMPT
keyboard and
displays
and responds
to
commands
and
functions.
The
top 16
bytes
of
on-chip program
memory
must
be used by the
PROMPT
system
to switch
between
monitor
and
user
programs.
It
requires
one
level
of
the
MCS-48
eight-level
stack.
Commands
PROMPT
48's
commands
are
grouped and
color-coded
to simplify
access
to the 8748's separate
program and
data
memory.
Registers, data
memory,
or
program
mem-
ory,
may
be examined and
modified with the examine
and modify
commands. Then
either
the next or previous
register
and
memory
locations
may
be accessed
with
one
keystroke.
Programs
may
be
exercised
in
three
modes. The go no
break
(GO
NO
BREAK)
runs
in
real
time.
The go
with break
(GO
WITH BREAK) mode
is
not
real
time
—
after
each
instruction the
MCS-48
program
counter
is
compared
against pending
breakpoints.
If
no
break
is
encountered, execution resumes.
The go
single
step
(GO SINGLE
STEP)
mode
exercises
one
instruction
at
a time.
Commands
are
like
sentences, with param-
eters
separated by
NEXT. Each
command
ends
with
EXECUTE/END.
In
addition
to
the
PROMPT
basic
commands,
thirteen functions
simplify
programming.
Each
is
started merely by pressing a hex
data/function
key and
entering
parameters as
required,
as
shown
in
Table
1.
9-10