Falcon 030 CPU (68030) Acceleration Modification
Designed by Peter Green
The author cannot be responsible for any damage to your
equipment, other software or hardware products, or physical or
mental well being caused by the use, misuse, abuse,
misinterpretation, or inability to use this hardware modification.
The author also makes no guarantee as to the compatibility of this
hardware modification, I only give an assurance that this
hardware modification will function correctly as part of my own
personal computer. By using this information leading to the
proposed modification you are agreeing to accept full
responsibility for any
circumstances arising from it's
implementation. If you do not agree with these terms
understand them, do not
attempt this modification.
- Warning 1: Opening your computer and changing it's internal parts
in any way will invalidate your machine's warranty.
- Warning 2: This modification will change video clocks which could
potentially destroy connected monitors, or any other connected peripheral
- Warning 3: If you lack sufficient technical electronic knowledge,
then you should not be attempting this modification.
- Warning 4: Don't let this put you off!!
Click here to download Peter Greens original
This information for CPU acceleration is SHAREWARE
This accelerator modification for the Falcon030 was
designed to give a little extra processing power to the 68030 CPU
and more specifically, to increase the bus through put for FPU
intensive programs to take full advantage of my FPU acceleration
mod (See FPU_ACEL.ZIP).
Test results using Gembench 3.25
(Note that % varies slightly, dependant on graphics resolution)
| ||CPU 16||CPU 18||CPU 36
|FPU 16||FPU 50||FPU 18||FPU 50||FPU 18||FPU 50
|Float math CPU||100%||141%||120%||153%||135%||180%
- Note 1: The 36MHz option was obtained by using both the
modification described in this text and the "PowerUp 2" mod.
- Note 2: FPU at 50MHz is in reference to 'FPU_ACEL.ZIP'.
- Note 3: With 6882 at 50MHz, CPU 18MHz performance is 102% of TT,
with CPU at 36MHz (PowerUp 2 fitted), performance is 120% of TT!! (Float math
only, TT in fast ram).
If you lack electronic experience, don't let this put you
off since it won't cost that much to get an experienced friend or
even qualified engineer to perform this modification, and should
still work out considerably cheaper than any other accelerator
board that can be purchased. Approximate cost for parts is under
Before you start hacking with your circuitry, it's worth
noting that my CPU is clearly labelled as a 16Mhz device (denoted
by '16' at the end of it's product number), but I have quite
happily had my CPU running at 36.4 Mhz, more than twice it's
stated operating speed. However, long term 'exposure' to this
kind of speed is unknown, and I strongly suggest that a
switchable version be made, only switching to high speed when
needing high perfromance from the CPU.
Warning: I strongly advise that you remove the internal IDE drive and
disconnect all external devices when performing this modification. As you will
be changing clocks, central to the CPU, should you make any errors it is
conceivable that data will be lost or the device damaged.
You may find it useful while testing this modification to run your 030 from
a television in ST medium resolution, as T.V. set's are protected on their
antenna inputs against high voltage,but monitors have direct connections.
First of all I have assumed that you have already had the
buffer modification applied to the Falcons clocks, if not then
If you haven't already got the buffer mod. fitted do this
now(!!), and forget about the CPU mod for the moment, making sure
that it functions correctly.
In principle, acceleration is extremely simple; just put a
faster crystal in place of the old one! However this is not with
out it's problems.
Figure 1 shows how simple this can be, just cut one wire
and solder in a new oscillator block.By using a 36Mhz block you
will have a CPU clock of 18 Mhz (the clock control 'glue' chip
divides by 2 before sending the clock to the CPU). However this
is a system wide clock, and will change the majority of
operations inside the 030. If you have successfully made this
modification, after switching on, all will look normal.
Note that if you are using any kind of graphic resolution boosting program
(E.g. Falcon Screen, Videl Inside, BlowUp, ScreenBlaster etc.) it is possible
that you will find strange things happening to the syncronisation of the
This is because there are only 2 clocks available for screen driving; 25MHz and
32MHz, and you have just changed the 32MHz to 36MHz!! It is possible that
prolonged exposure to "wrong" syncronisation signals could damage your
In practice I could not see any
difference between 32 and 36
Mhz when my screen was set to; 2 colours, 80 columns, double line
OFF. The monitor used is an ancient LOW resolution mono which I
have converted to run in high resolution VGA. If this can take
the pace, anything should be able to!! A reasonable rule of thumb
is that if your screen looks stable, then it is
stable, but no
Back to the plot, all being well you should now have a nice
faster 030, but... your keyboard or mouse won't work (pretty
fundamental I think!!).
Well, that didn't inspire you with confidence did it? Here's
how to do a proper job.
What I haven't mentioned up until now is that any change in
CPU clock will also make the MIDI ports, keyboard and mouse un-
usable (!!), just a 'slight' problem......
This is beacause the 500 Khz clock which feeds both the 6850
serial keyboard driver and the 6850 serial MIDI driver comes from
the glue chip and is clock/64, therefore at 36 Mhz the clock is
now 562.5 Khz.
You must first locate 'U 52' (6850) which is the serial
interface for the keyboard, this can be found just above the
recess in the PCB where the mouse and joy stick sockets are
placed when the keybaord is removed (Bottom right).
Now the tricky bit, you must find and cut pin 3 on this chip
and bend it upwards, leaving enough pin left to be soldered to.
Check this connection first with a continuity tester, it will
have a direct connection to pin 23 on the expansion socket 'J 20'
It will also have a direct connection to 'U 24',(6850) pins 2+3,
which is located underneath the power supply and just right of
the ROM ports and slightly below the MIDI sockets.(This is the
MIDI serial converter). Now solder a wire between pin 3 of U 24
and pin 3 of U 52, and another wire which from one of these two
points which will be the new 500 Khz input.
There is no easy way to do the next part, coming out of the
'GLUE' chip 'U 56' is a PCB track which must be cut, this is very
small and there are lots of tracks on this part of the PCB. This
can be found between the 68030 (U 55) and the GLUE chip (U56).
There is a wire that runs out of U 56 just underneath R 217, it
then takes a sharp bend before straightening again and is
terminated by a small 'through PCB' hole about 0.75 cm to the
right of 'U 55' 68030. Before cutting carefully check that
this is in fact the correct connection with a continuity tester
and that it has zero resistance between pins 2+4 on 'U24' and pin
3 on 'U52', and pin 23 on the expansion socket 'J 20 ' (just
left of the CPU U 55, and forth pin to the left on the bottom
row).If you are satisfied that you have found the right wire then
cut it about 1cm infront of the through-PCB hole.
Now that you have separated the two serial drivers from the
clock on the glue chip (U 56) they must now be fed with a new
500Khz clock. By far the best option would be to use a ripple
counter chip to divide the 32 Mhz clock (74HC4024), I simply
didn't have one fast enough (an HC device MUST be used) so I used
a small 500 Khz ceramic resonator (crystal) and buffered it using
a CMOS 4069UB chip in stead. Both circuits are included in the
This circuit is very straight forward, it comprises just 2
chips and a switch. A 74HC08 AND gate is used as a means of
switching on/off the clock sources. The gate used to switch the
32Mhz clock is kept at high level by a 10K pull-up resistor,
keeping this clock permanently on, this same pin is also fed to
one NOR gate in the 74HC02, which is used here simply as an
inverter. This inverted signal is then fed to the control input
of the 36 (40) Mhz clock source, this enables the two clocks to
be instantly switched between simply by shorting to 0V the pull-
up voltage from the 10K resistor. The outputs of the two AND
gates are then fed to the two inputs of one of the NOR gates
74HC02, strictly speaking this should then be inverted since the
gate is a NOR rather than an OR, but in practice this makes no
difference at all, I actually chose not to invert the clocks
again to keep them as clean as possible.
I also chose to mount my 36.4Mhz oscillator block on the
same piece of VERO board that these 2 chips were mounted, the
whole thing measures around 5 X 6 cm, and I have located this
just left of the fan, just below the RAM, where there is a nice
little space for it.
While you are at this stage I see no reason why it may not
be possible to push the clock even higher, I am not able to test
this at the moment since all I have is a 36.4 Mhz block, and my
next highest is 45 and 48Mhz osc.blocks which do not work. I can
imagine getting up to 40Mhz or even around 42Mhz if you're really
Switch-over is pretty much rock solid, and you'll have to
switch about 10-15 times at high speed to cause a crash, so in
normal use this will not happen. If you encounter problems, or
are paranoid about a crash happening during important work, there
is a very reliable solution; disable all processing, see below.
You only need to do this if you have problems
Fortunately there is a convenient 'process halt' built into
the system designed to allow expansion boards. This is very
since to use this it will require no soldering or cutting of the
PCB. To locate this, look just left of the CPU (U 55, 68030)
where you will find 2 rows or pins labelled 'J 20'. Plugged into
this you will find a small plastic jumper plug, you will also
notice that there is a white mark printed on the PCB to show it's
exact position (W 11). This plug should be removed and all that
you need now do is connect a switch to these two pins, either
soldered directly to the pins, or by using a small plug connected
to a switch (as I used).
Using the process switch for CPU clock change
This may seem a little awkward to use, but is in fact by far
the best option in terms of it's lack of complex switching
When you want to switch first take the process switch into
OFF position, then click or move the mouse until the cursor
disappears (or attempt a keyboard command if not running a gem
program), the whole processing within the computer is now fully
'frozen'. CPU clock switching can now be performed without
harming or crashing the system. Once a new clock has been
switched over, the process switch should then be put back to the
'ON' position. Instantly the system will pick up from the last
point you were at and continue at the new speed. This process
must be repeated when ever a new clock speed is required.
- Proc switch off
- Click mouse
- Switch CPU clock
- Proc switch on
I have not yet experienced problems of any kind relating to
the floppy drive (format, copy disk image, copy files etc.) It is
possible that you could get trouble, but so far at 36Mhz my
floppies are happy. Floppy writing has not
been tested at 40Mhz,
as I've yet to obtain a 40 Mhz block, please consult the text
relating to protecting floppies contained within 'FPU_ACEL.ZIP'
if you go to 40 Mhz and find problems. You can obtain a 16 Mhz
clock from pin 12 of the 74HC4024 chip used to give a 500Khz
clock to the Keyboard and MIDI ports. Only do this if you need to!
Music sample rates
If you are using the AD/DA converters for musical use, it is
possible that sampling rates will be effected. However I have
tested 49, 32, 24, 19, 16 Khz at both
16Mhz and 18Mhz (36Mhz) and
audible pitch change at all. I even switched from 16 to
a recording! I found NO problems or obvious pitch
shift at all, everything seemed as normal
If an external digital source is used for music, this should
never be a problem since 44.1 Khz provides it's own external
clock to the DSP port, also the DSP has it's own dedicated 32 Mhz
clock which cannot be changed.
It is also possible that there will be tempo changes
(B.P.M.) within sequence programs. 'LOGIC AUDIO' and 'NOTATOR
LOGIC' have been tested and do not suffer tempo problems.
'CUBASE AUDIO', and others have not been tested.
All files in this archive, are protected by copyright. The author
does however, reserve full copyright of this modification.
The archive may be distributed freely, so long as all the files
are distributed together in a single archive.
Anyone using this information to carry out the described
modifications should register with the author. If you register
you will not only get enormously large warm feeling inside, but
will also be sent (if requested) details of further modifications
regarding changing the microphone inputs and headphone output to
give standard line levels, and a (simple, but powerful) noise
reduction circuit, and/or FPU acceleration. (Please state).
If you find my information useful please register with me by
sending me œ5 - œ15 (U.K.). I need your registration fees !!!
I'm a humble student trying to save up for my Masters Degree;
there's no government grant, and I don't come from a rich family!
WAKE UP! education is the life blood of a healthy society.
To register, or send any donations to help put me through
179 Church Road
Please feel free to add comments or possible updates
concerning CPU acceleration (e.g.if ATARI ever produce a Falcon
040 ),and if necessary additional graphic images to this archive,
but the full original documentation must remain intact; any
additional material must be clearly labelled in a folder separate
to the original. I do however give my permission for additional
material to be re-archived with the original files into one new
archive with a new name (e.g. CPU_ACL2.ZIP).
And finally... Build a wind generator, you know it makes sense!
They don't make noise (far,far less than cars, air planes,
trains, BIRDS, WIND!! )I recently visited a local generator which
was spinning very fast in a strong wind and took note of it's
noise level. I then walked less than 20 meters to a group of 2
or 3 averaged sized trees blowing in the wind, and was absolutely
astonished to find that the generator was completely swamped by
the noise of these trees blowing in the wind, the turbine could
not be heard above the sound of the trees at all!
What does this say for the main argument of the anti-wind lobby?
PETER GREEN 27/6/95
HTML-version by Jo Even Skarstein