Nemesis

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Nemesis accelerates the entire Falcon system by 50% therefore most software will run without modification. There are, however, some pitfalls to avoid.

In common with all system accelerators, Nemesis modifies the system clock. Since this clock supplies the 32MHz dot clock to the Videl chip this signal will be 32, 40 or 48MHz depending on the status of the Nemesis switches. Software which depends on the system clock being 32MHz, or requires a 32MHz dot clock to provide enhanced resolutions, will fail. Obviously this affects RGB users most because RGB resolutions use the 32MHz clock.

A switch has been provided on the Nemesis board to allow the 25MHz clock to be replaced with a 32MHz one. This allows the Falcon to be accelerated with an RGB monitor and still produce sensible video. For this reason it is inadvisable to change the dot clock when setting up the display using the hardware registers while running on an RGB monitor. Either retain the current dot clock or use Vsetmode to change resolution.

Avoid using instruction sequences to provide delay loops in timing critical code. Any FOR ... NEXT type construct will take 33% less time when Nemesis is running at 48MHz regardless of language. Use the MFP timers for accurate delays. This one applies to any accelerator.

That's it. Generally any software which is completely clean and doesn't set up it's display using the hardware registers will work perfectly well.

Nemesis Accelerator Photos

  • Nemesis TOP.jpg
  • Nemesis BASE.jpg

Nemesis Buffer Photos

  • Nemesis Buffer TOP.jpg
  • Nemesis Buffer BASE.jpg

Updates & Corrections to manual

PLEASE READ FIRST BEFORE INSTALLATION, ESPECIALLY POINTS 8.1 & 9.2 

NEMESIS SYSTEM ACCELERATOR
Last edited 18 Apr 97

Updates and corrections to manual
---------------------------------

=========================================================================
    FIRST AND MOST IMPORTANT - READ THIS TEXT FILE AND THE MANUAL 
       THOROUGHLY BEFORE STARTING WORK ON THE NEMESIS UPGRADE.
=========================================================================

Nemesis is copyright 1997 Black Scorpion Software Limited. 

=========================================================================
GETTING NEMESIS FITTED
=========================================================================

If, after reading through the manual, you decide it is a little heavy 
going(!), contact TITAN DESIGNS for more information on the available 
fitting services.

The following questions really need answering first;

1. Type of memory fitted? See below.

2. Type of IDE drive fitted? (if any)

3. Is the capability of support for RGB monitors required?
	- this is an optional extra costing only œ5.00.

4. Hard disk driver software used?

	- AHDI and HD Driver are fine. The only problems to date seem to 
	be with some versions of ICD software, although we have not been 
	able to determine exactly what the problem is.

If you do decide to get Nemesis fitted by someone recommended by Titan 
Designs, please ensure that payment for the fitting service ONLY is to the 
person or company performing the upgrade - we will advise on this.

If you have a Desktopper-style case, then we would much prefer to receive 
just the motherboard, the IDE drive and the floppy - we do not like these 
cases and dismantling them is very time-consuming. If you do decide to 
forward the complete system, with case, then an extra œ5 will be levied 
for handling charges.

This additional levy (œ5) also applies to owners of recased Falcons, 
except for the C-Lab MK.X.

IN ANY EVENT MAKE SURE THE COMPUTER IS PACKED EXTREMELY WELL!!! Titan 
Designs or it's agents cannot be held responsible for any damage sustained 
during transit.

Sending on the IDE drive is preferred but not essential. The reason for 
this is because we would prefer to test the complete fitted installation 
and ensure that the software is correctly configured. It has been noted 
that some large IDE drives do not work with Nemesis running at 48MHz or 
sometimes even 40MHz. This situation is rare.

External SCSI drives need not be forwarded.


=========================================================================
3.1 PACKAGE CONTENTS (page 6)
=========================================================================

Only the 150pF capacitor is supplied as we have yet to find a Falcon which 
needs the 82pF device.

=========================================================================
INSTALLATION OVERVIEW (page 7)
=========================================================================

- FalconWing Memory Boards

If you do have FalconWing fitted or any other memory upgrade board that 
uses 30-pn SIMMS, these are almost certainly NOT SUITABLE for use with 
Nemesis. The design of the FalconWing PCB creates an unacceptable amount 
of video noise to the extent where the screen is unviewable.

  Solution: Not an easy one this... You could try to sell on the 4 x 4MB, 
  30-pin SIMMs to a PC or Mac user (providing their machines still support 
  these SIMMs), but they are not in great demand.

- Original ATARI 14MB memory board

NOTE: This ONLY affects the original Atari 14MB memory boards, with memory 
chips rated at 80ns. These boards produce a similar effect to the 
FalconWing and, while not as bad, can still produce very noisy screens.

  Solution: As with the FalconWing - not easy... You really need to find 
  another Falcon user who won't be having a Nemesis board fitted!

Contact Titan Designs for the best price on SUITABLE 14MB memory upgrades 
- we only use 72-pin, 60ns EDO Panasonic TAB SIMMs - the very best!

=========================================================================
5.4 Preparation
=========================================================================

Please note the following;

If an existing buffer mod. is fitted to your Falcon, this will need to be 
removed. Normally these are fitted across the GAL, U63.

If a Power Up2 is installed, then it will be necessary to remake a solder 
junction. This can be found just in front of the PSU and is marked 'U46'.

Locate the fourth (4th) set of pads from the LEFT and remake this joint.

It is also possible that this juncton has been broken at some time in the 
past, therefore it is worth checking as a matter of course.

=========================================================================
6.3.2 Continuous black screen (page 14, 2nd para.)
=========================================================================

The mention of "... moving the BLUE wire to the TOP of R217..." should 
read; "... moving the BLUE wire to the *BOTTOM* of R217..."

3rd para.
---------
Should read; "The installation can now be *retried*...". Silly typo!

=========================================================================
7.2 LOCATION (of the Nemesis board - pages 18/19)
=========================================================================

When mounting Nemesis inside a standard (not recased) Falcon, we do 
recommend that the fan is removed and replaced inside the top metal 
shielding. Nemesis is then mounted above the vacant hole.

However, do not use the solder pads (used to mount the fan bracket onto 
the Falcon motherboard) as ground points for Nemesis - these are not 
connected to ground at all (caused us a few panicky moments!). Use the 
outer rail of the Falcon motherboard instead.

These solder pads do make a very solid joint from which to mount Nemesis 
(using a paper clip is ideal!) - just don't rely on them for grounding.

=========================================================================
8.1 IKBD PATCH (page 20)
=========================================================================

Item (d) mentions that "some" Falcons benefit from having both pins 3 & 4 
lifted and joined. It now seems that "ALL" Falcons work correctly having 
this mod. done, and this can be considered the *only* method. The diagram 
at the bottom-right of the page is also incorrect in this respect.

sub-section (k) (page 21)
-------------------------
The thick red (power) wire on some Nemesis boards might be too short to 
reach the positive (+) pole of C147. This will mean lenghtening the wire, 
however make sure that any solder joint is well insulated!

=========================================================================
8.2.3 If the machine boots up normally... (page 23, 2rd & 4th para.)
=========================================================================

Ignore this reference - the IKBD chip should have BOTH pins (3 & 4), 
lifted and connected together, as mentioned above (8.1).

=========================================================================
9.2 ACCELERATING THE DSP (page 27, sub-section (d))
=========================================================================

"Solder the BROWN wire to the newly exposed PCB track", should read
"Solder the *YELLOW* wire to the newly exposed PCB track.

=========================================================================
9.3 DOUBLE-CLOCKING THE FPU (pages 27/28)
=========================================================================

Under certain circumstances, we have discovered that some later revision 
motherboards cannot cope with the FPU being double-clocked - irrespective 
of the speed of the FPU.

Unfortunately there is not a solution to this problem and it will be 
necessary to revert back to using the ORANGE wire from the Buffer instead.

This will still permit an FPU speed of 20 or 24MHz depending on the 
Nemesis setting.

=========================================================================
10.4 RGB SYNC FIX (page 30)
=========================================================================

The VGA Sync bug mentioned refers to tiny 'flecks' that can sometimes be 
apparent on some VGA monitors (in the main, inexpensive 14" VGA seem to 
suffer most).

=========================================================================
11.1 REFITTING FAN (optional for Std. Falcon users - pages 30/31)
=========================================================================

We do realise that it's impractical for most people to have a bench 
mounted pillar drill with a 38mm hole saw(!), but using this method does 
ensure that the components inside the Falcon do remain adequately cool. 
Contact Titan Designs if you require this modification done.

PLEASE NOTE:
The mounting holes for the fan detailed in the diagram are incorrect. They 
should use the top-right and bottom-left holes in the metal shielding.

Please contact us if you're unsure about this part!

=========================================================================
12 SOFTWARE (pages 31 to 33)
=========================================================================

All updates to the Nemesis software are freely available from our new Web 
download area (see the foot of this page for the URL).

=========================================================================
12.3 & 12.3.1 NEMESIS SPEED SETTINGS (page 32)
=========================================================================

All the Nemesis software switches are now PRG files, not TOS, and can be 
placed in the AUTO folder as desired.

=========================================================================
12.5 SPEED DETECTION (NEMESIS.PRG (page 33)
=========================================================================

Last sentence should read;
"Placing NEMESIS.PRG as the first file after the Boot Manager (if used), 
will assist in speeding up the AUTO-loading process in conjunction with 
the NEM_HI or NEM_LO software switches."

=========================================================================
APPENDIX 1.1 GENERAL SYSTEM STABILITY (pages 34/35)
=========================================================================

We cannot really emphasise enough the need for SOLID ground connections. 
We have discovered this can have a marked effect on the stability of 
Falcons, so if you are getting some odd results with Nemesis installed try 
fitting additional ground points from the Nemesis PCB (the 'e' points) to 
the outer rail of the Falcon PCB.

=========================================================================
APPENDIX 1.2 SCSI & Audio DMA Problems (page 36)
=========================================================================

Ignore both items (b) and (c). The 82pF is not included and you should 
only need to use the 150pF capacitor.

Fitting an Afterburner to a 'Nemesised' Falcon is an exception to this 
rule and further advice will need to be taken from Titan Designs/BSS.

=========================================================================
ADDENDUM - NEMESIS PRINTING (page 39)
=========================================================================

The mention of Nemesis printing problems, in the ADDENDUM, appears to be 
related to the MagiC OS only, and does not seem to affect other OS 
configurations.

To get around the problem inside MagiC, switching the Nemesis clock value 
to 20/40MHz does permit printing under these conditions. If/when we have a 
suitable fix for this problem it will be posted on the various BBS and 
on-line conferences - sorry if you haven't got a modem yet!

=========================================================================
ADDENUM - SPEED INDICATION CIRCUIT
=========================================================================

This small section is a last minute addition to the manual, and is useful to those 
Nemesis users who would like an indication of the current speed state. Due to lack of 
time, we are unable to provide a circuit diagram, but will post information for this on 
42BBS, Cix and NeST, when ready. Alternatively, contact us for more information. 

Using a bi-colour, or tri-colour LED means that different colours can indicate either 
40MHz or 48MF^z, with an off state meaning Nemesis is inactive. An alternative 
method is to use two separate LED's with an in-line resistor to one leg of each LED. 

Signal Pins 

The pins used to indicate the current Nemesis state are pin 5 of U24 (48MHz), 
and pin 5 of U52 (40MFHz). 

? Make absolutely sure that no part of the circuit shorts to ground (except the 
ground pin, of course!). If this did happen, the Falcon could get damaged.

=========================================================================

Apart from all this very necessary gumph, have fun fitting Nemesis and we 
feel sure that you'll enjoy all the benefits that it offers!

Remember we are only a phone call away, so if you need any further 
assistance, FIRSTLY RE-CHECK THE INSTALLATION TO MAKE ABSOLUTELY SURE 
THERE ARE NO ERRORS and, if this doesn't reveal anything, please contact;

=========================================================================
TITAN DESIGNS LTD
6 Witherford Way, Selly Oak
Birmingham B29 4AX. U.K.

Tel: +44 (0)121 693 6669
Fax: +44 (0)121 414 1630

e-mail: 100345.2350@compuserve.com

Web: http://ourworld.compuserve.com/homepages/TITANWEB/
=========================================================================

Installation tips

The stock Nemesis wires that come with the board are in the most part unsuitable for a stable installation as they provide no RF shielding which can can cause the board to perform unpredictably and in an unstable manner. It is recommended to replace the majority of the stock coloured wires with mini COAX cable and connect the shielding from each cable to the numerous 'e' points (same as 'G' points on diagram below) on the Nemesis board and the main ground that runs around the perimeter of the Falcon motherboard.

Colour Jumper Number COAX Y/N FUNCTION
Brown J1 Y
Red J2 Y
Orange J3 Y
Yellow J4 Y
Green J5 Y
Purple J6 Y
Grey J7 Y
White J8 N Nemesis board switching
Black J9 N Nemesis board switching
Blue J10 Y
Pink J11 N Nemesis board switching
Red (thick wire) +5V N Power
e N Ground

Wiring Diagram

Nemdg100.png

External Links

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