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1991-02-09
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6KB
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177 lines
EM6805 - A Simulator for the Motorola MC68HC705C8 Microcontroller
Version 1.1 January 1991
This program is a development tool for the testing and simulation of the
MC68HC705C8 microcontroller. The object program, in PROM image format, is
executed in the virtual machine. It is possible to follow the program
through its instructions to verify that the program is correct before
committing it to silicon.
SYSTEM REQUIREMENTS:-
IBM or compatible system, 1 floppy drive, 256K, EGA/VGA screen
USAGE:-
From the opening screen, if an unregistered version is used, the oportunity
to perform registration is given. Registration consists of entering the
users registered name and registration number. If the version is already
registered, then the registration screen is bypassed and the user is
prompted for the name of the PROM object file. No default path, name or
extension is provided. Note that the PROM file must be exactly 8,192 (8K)
bytes long, i.e. an EPROM (2764) image.
With the target program loaded, a number of commands may be used.
F1 - HELP screen.
F - file image save
I - interrupt service
G - restart (1FFE-1FFF)
E - execution rate change
X - change index register
A - change accumulator A
P - change Program Counter
S - change Stack Pointer
B - set breakpoint.
C - clear breakpoint.
M - memory examine/alter.
R - run until breakpoint
or illegal address
T - toggle trace print
+ - single step
Q - quit.
F1 Pops up a help window showing the available commands as above.
F Saves the target program back to disk. This is useful after some memory
locations may have been changed as a result of the simulation and
debugging session. This feature is only available in the registered
version.
I Interrupt posting. While running, it is possible to raise an interrupt
at any time by pressing the I key. This is effectively providing the
ability to cause an external interrupt at any time. Should interrupts
be enabled, then the progress of the interrupt routine may be observed
(and debugged!)
G Restart the object program. This has the same effect as providing a
power on reset or similar hard reset to microcontroller. Note that
the target program is not reloaded but uses the program that may
have had alterations made.
E Change the rate of executing the instructions in the simulator. The
rate can be altered from 100+ instructions/sec to approx 1 instruction
per 5 seconds. This feature is not available on the unregistered
version.
X Change the index register.
A Change the accumulator.
P Change the program counter.
S Change the stack pointer.
B Set a breakpoint. Program execution will run until a breakpoint is
reached. Up to 10 breakpoints may be set at one time.
C Clear a breakpoint that was previously set with a B. Note that the
breakpoint must be explicitly defined as no check is made against
those that may be set.
M Memory examine/alter. The full 4-digit hex address must be used in
specifying the address. a 2-digit Hex number is required for the data.
Note that the first 32 bytes of I/O are shown at all times on-screen.
R Run the program at the rate specified by the E command. Execution will
proceed until 1) a breakpoint is reached, 2) the program runs into
illegal memory space (above 8K memory space) or 3) the user presses
the ESC key.
T Toggles the print trace function. If the printer is on-line and ready,
a trace of the program will be printed. If the printer is not ready
and available, then the emulation will continue without printing. This
feature is not available on the unregistered version.
+ Single step one instruction for each depression of the + key.
Q Quit the program.
Obviously it is not possible to interface to the external world as
in a full micro simulator but it is possible to reflect the external
inputs by pausing execution and changing the appropriate I/O register
to reflect the state of the external device and then continuing the
execution of the program.
This program was developed as a result of a need for proving software
for the MC68HC705C8 microcontroller and has speeded up the development
cycle considerably. It is written in QuickBASIC ver 4.5 and uses a
number of library routines for screen presentation from the Toolbox
of Christy Gemmell to whom acknowledgement is given.
Although this variant is written specifically for one version of the
Motorola 6805 family, it would be relatively easy to adapt it for
other members if there is sufficient interest.
DISCLAIMER
The software is provided without liability and it is the users
responsibility to to determine the suitableness for his use.
______________
REGISTRATION:- The registration procedure buries the registration
information in the program file in the registration process. Once
registration has occurred, the program should not be patched or
altered as this will inevitably cause failures.
To assist with the funding of software such as this, registration
in accordance with the principles of "Shareware" is recommended.
Registration ($AUS50 or $US40) may be obtained from:-
Peter J. Ford
Polygon C.S.S.
7 Sherman Street
Forest Hill
Victoria
Australia 3131
Registered users have the extended facilities of the program and support
for this and subsequent releases of which they will be notified from
time to time.
This software may be freely distributed in its unregistered form with
no charge being made for it apart from a nominal charge not exceeding
$10 for copying.
Peter J. Ford - author.