Breaking the 10Mhz barrier
By Andrew Roughan
Copyright (c) 1992 Apple Users' Group, Sydney
Republished from Applecations, a publication of the Apple Users' Group, Sydney, Australia.
Hot news travels fast these days, and seemingly none travels faster than the news of "14Mhz" 65C816 chips. The undercurrent at Kansasfest always brimmed with comments about Tim Meekins running his Transwarp GS accelerator (TWGS) at 13.75Mhz or Steven Chiang running at 14Mhz. For those of us without accelerators, running at 2.8Mhz, this is mind bogglingly fast!
The chips in question originated from Sanyo who re-engineered the 65C816 to boost its performance. The Sanyo chips run at higher speeds without needing higher voltages or cooling systems.
Western Design Center (WDC - the company behind development of the 65xxx series) purchased a large batch of these chips directly from Sanyo and have made them available to people wishing to upgrade their TWGS boards.
WDC have always been able to provide limited quantities of 'engineering parts' which performed better than 7Mhz, but the Sanyo batch has brought the average performance to greater than 12Mhz.
So with a faster processor available, are manufacturers offering faster accelerators? Zip Technology offered an upgrade for a short time and now list a 14Mhz Zip GSX card. Applied Engineering do not offer anything for TWGS owners, but fortunately it is easy enough to do it yourself.
The procedure for upgrading a Zip GSX board involves cutting traces and replacing logic array circutry, as well as purchasing a faster processor and oscillator. At this stage the process is not well documented and owners are advised to purchase the upgrade throught Zip Technology directly.
Available Documentation
Until now, for most of us at with 7Mhz Transwarps, the quest for speed has been a little daunting. Getting accurate upgrade information and finding parts suppliers has been difficult.
The article by Andrew Hall, prepared for Western Design Center and published in September 1991 Applecations, outlines four steps for getting the best possible speed out of the TWGS.
The National AppleWorks Users Group (NAUG) publication 'AppleWorks Forum' has three articles containing very detailed, accurate and informative information written by John Link. The issues are March, April and May 1991. These three issues are considered 'must read' material and are supplied by WDC to any prospective TWGS upgrader. When you contact WDC to purchase a 65C816 chip, they will insist on sending this document (by fax or mail) before processing your order.
The aim of this article is to give additional information not generally available. The upgrading steps are still the same, but now the faster parts available make it easier to get a faster speed which may tempt more Transwarp GS owners to break the 10Mhz barrier.
Prerequisites
The TWGS needs ROM version 1.5 (or greater) to work at speeds greater than 7Mhz. The current ROM can be obtained directly from Applied Engineering for US$20. The NAUG document describes how to replace the ROM.
It is recommended that the TWGS have the 32k Cache upgrade. This will give you the latest ROM, faster cache memory and complimentary performance improvements. The 32k Cache upgrade can be purchased locally from Two Series Software for $99.
The other speed dependent parts on the TWGS are the GAL chips which are seated together on the right hand side of the card. The minimum versions that are known
to work are TWGS1A1, TWGS2B1, TWGS3E1, TWGS4B1, TWGS5A1, TWGS6A1, TWGS7A1, TWGS8B1. A fast GAL chip set is available from LRO Computer Sales for $79 + shipping. Applied Engineering's code for the set is 10MHZPALKIT.
Obtaining the Microprocessor
Replacement 65C816 chips are obtained directly from WDC. The processors cost US$95. Shipping by airmail is an extra US$5. NAUG members can obtain 65C816 chips for US$71.25. I really shouldn't point out that if a group got together to purchase 65C816s in one shipment, that it would be worthwhile for one person to join NAUG - membership is US$31.
Obtaining the Crystal oscillator
The WDC supplied document explains why the oscillator must be four times the speed that you wish to run your system at. The shmoo plot supplied with the processor will enable you to identify what speed the processor can run at. You then must obtain the appropriate oscillator.
Oscillators are available on this side of the Pacific Ocean from Clarke & Severn Electronics. Different speed oscillators have different prices ranging up to $12. Contact them for information as to pricing and availability. Non "off the shelf" speed oscillators can also be ordered at a cost of $21 each.
The TWGS uses a 1/2 TTL oscillator. The oscillators supplied by Clarke & Severn are standard size TTL oscillators. This means you will need to modify the oscillator to fit the TWGS. The WDC supplied document describes one method of doing this. Another is to obtain a 16 pin DIP socket from Dick Smith Electronics for 40 cents. Cut 8 pins off of one end, and solder a jumper wire between the 8th pin (cut off) and the 4th pin (not cut off) on each side. This method has the added advantage of making oscillator swapping an effortless task whereas the NAUG method involves modifying the actual oscillator.
As an alternative to Clarke & Severn, you may like to try Digi-Key in the USA. Digi-Key have the following 1/2 TTL oscillators which fit into the TWGS with no modifications:
Mhz Part Price (US$)
------ ------ -----
32 SE1101 3.60
33.33 SE1102 3.60
36 SE1103 3.60
40 SE1104 3.60
42 SE1105 3.60
46 SE1106 3.60
48 SE1107 3.60
50 SE1108 3.60
55 SE1109 3.60
60 SE1110 3.75
If you wish to look for other alternatives, make sure that you get TTL or CMOS oscillators. Sizes are 1/2 or standard. They come in metal and plastic
bodies. The plastic ones work just fine and are possibly cheaper.
Obtaining faster cache memory
The standard TWGS 8k cache memory is 45 nanoseconds (ns). The 32k cache memory is 35ns. 35ns is supposedly fast enough for 14Mhz so you may not need faster SRAMs than this. Experimentation is still continuing in this area. SRAMs used by
the TWGS and Zip GS are 32768x8 general purpose SRAMs. Try and get chips needing the lowest power requirements.
Sony make a very low power 25ns chip, CXK58258B-25LL, and a 15ns chip CXK58258A-15. VLSI Tech make 25ns, 20ns and 15ns chips: VT62832UHL-25, VT62832UHL-20, VT62832UHL-15. Other 25ns chips are Mosel, MS62256-25, and Paradigm, PDM41256L-25.
All the chips mentioned are available in 28 pin DIPS, with tri-state outputs. Some may only be available in .3 inch or .6 inch widebody packages. My TWGS 32k Cache upgrade takes the .3 inch packages but you should check yours to make sure you get the correct size, otherwise some messy soldering could be involved.
Increasing the Power Supply
Increasing the power supply increases the performance of the processor, oscillator and GAL chip components thereby giving improved system performance.
There are two methods of increasing the power supply to the TWGS. The first is to increase the voltage level output from the power supply which affects the whole system. Adjusting the power supply output is not a user servicable operation. Applied Engineering sell a 5.25 volt supply to NAUG members. The second is to use the 12 volt supply line on the TWGS edge connector, see Andrew Hall's article for this procedure.
Running your 65C816 higher than 5.5 volts is asking for trouble. The buffer chips in the TWGS and the IIgs are TTL and the design tolerances on those don't guarantee they will survive anything above 5.5 volts. There's going to be some drop, so feeding the 65C816 5.6 volts would probably work since the rest of the machine will still see 5.5 volts, but it is not recommended to go above 5.6 volts under any circumstances.
System testing
You should allow a significant period of running time to make sure that your system is reliable. Your system may work well when cool but crash unmercilessly when warm.
Success Stories
Steven Chiang (DreamWorld Software) 14Mhz
Tim Meekins (Procyon) 13.75Mhz
Chris Deschu (Internet user) 13.75Mhz
Chris Nelligan (AUG Vice-president) 12.5Mhz
Cameron Brawn (AUG Apple // sysop) 11.5Mhz
I am currently running my ROM 3 system at 12.5Mhz. I purchased a ROM 1.8S Transwarp GS with the 32k cache upgrade directly from Two Series Software.
The GAL versions are TWGS1A1, TWGS2B1, TWGS3E1, TWGS4B1, TWGS5A1, TWGS6A1, TWGS7A1, TWGS8B1. I bought a WDC engineering part 65C816 for $180 (including UPS freight and duty), a 50Mhz oscillator (to run my system at 12.5Mhz) from Clarke & Severn for $7.50. I have not purchased faster SRAMs or modified the power supply.
PARTS SUPPLIERS
High speed 65C816 processors are available from:
The Western Design Center Inc. (WDC)
2166 East Brown Road
Mesa, AZ. 85213
(602) 962-4545 (voice)
(602) 835-6442 (fax)
Talk to Deborah Lamoree when you call.
Oscillators are available from:
Clarke & Severn Electronics
PO Box 1
Hornsby NSW 2077
(02) 482-1944 (voice)
(02) 482-1309 (fax)
Digi-Key
701 Brooks Ave S
PO BOX 677
Theif River Falls, MN 56701-0677
(218) 681-6674
US$5 handling charge on orders under US$25.
Fast GAL chip sets are available from:
LRO Computer Sales
(815) 338-8658 (voice)
(815) 338-4332 (fax)
It is recommended to make sure that the item is in stock before offering payment details.
Transwarp GS ROMs are available from:
Applied Engineering
3210 Beltline
Dallas, Texas 75234
(214) 241-6060 (voice)
(214) 484-1365 (fax)
Transwarp GS 32k cache upgrades are available from:
Two Series Software
PO Box 1
West Hoxton NSW 2171
(02) 606-9343 (voice/fax)
Fast SRAMs are available from:
Sony (714) 220-9100 or VLSI Tech (408) 434-3100
National AppleWorks Users Group
Box 87453
Canton, MI 48187
(313) 454-1115
14Mhz Zip GSX cards are available from:
Zip Technology
5601 West Slauson Ave
Suite 264
Culver City CA 90230
(310) 337-1313 (voice)

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