WDC's W65C22N - the VIA are still made!

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eslapion
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WDC's W65C22N - the VIA are still made!

Post by eslapion »

For a good while I was aware Bill Mensch is still involved in making and selling 65XX series of chips.

The Western Design Center still makes CMOS versions of these chips that can run considerably faster than the ones made by Commdore 30 years ago. The are distributed by Mouser in Canada and the US.

However, they do have minute differences that can cause compatibility problems.

For a few years now, the WDC has been making a special version of the VIA called the W65C22N (the N stands for NMOS compatible) which is a direct drop-in replacement of the old MOS 6522 but with the bug that precented high communication speeds with early VIC-20s fixed.

I tried two of them in my "cool" 1541 drive and I find them amazing. They work exactly like the original 6522 chips but they consume only a fraction of the power and produce no heat at all.

Mouser sells them for 6.95$US each.

See:
http://www.westerndesigncenter.com/wdc/w65c22-chip.cfm

http://www.mouser.com/ProductDetail/Wes ... be%2fco%3d

I suspect they will work just as beautifully in a VIC-20


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Re: WDC's W65C22N - the VIA are still made!

Post by eslapion »

I just modded my "cool" 1541 drive by adding a Rockwell CMOS R65C02P1 and I am baffled by the results.

Normally a 1541 that's idling will draw about 630mA on the 5V source and it will vary very little if the drive is spinning. The 12V load is about 100mA when idling and it jumps to around 800mA when the drive starts spinning.

I just hooked up the drive to my Xantrex workbench PSU and I noticed the 5V idle current is down to 410mA. That's a whopping 35% drop in power usage. None of the 65CXX chips produce any heat at all.

Only the old ROMs still dissipate heat and I think I will replace them with nice modern 27CXX PROMs too.

That's cool... pun is intended.

8-)
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Re: WDC's W65C22N - the VIA are still made!

Post by Zibri »

So the right one for a 1541 should be W65C22N6TPG-14 right?
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Re: WDC's W65C22N - the VIA are still made!

Post by eslapion »

Zibri wrote: Thu Nov 05, 2020 12:25 pm So the right one for a 1541 should be W65C22N6TPG-14 right?
I just checked and Mouser says you're correct. That's the product code for the PDIP-40 package.

These chips are also available in surface mount PLCC-44 package.
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Re: WDC's W65C22N - the VIA are still made!

Post by rmzalbar »

eslapion wrote: Tue Sep 22, 2015 9:08 pm I just modded my "cool" 1541 drive by adding a Rockwell CMOS R65C02P1
Is it possible for the 65C02 to cause compatibility issues with custom disk drive loading code, i.e. copy protection or speed loaders?
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Re: WDC's W65C22N - the VIA are still made!

Post by eslapion »

rmzalbar wrote: Fri Nov 06, 2020 7:04 pm Is it possible for the 65C02 to cause compatibility issues with custom disk drive loading code, i.e. copy protection or speed loaders?
The Rockwell CMOS version of the 6502 will not support most illegal opcodes of the NMOS based MOS 6502.

See:
http://ist.uwaterloo.ca/~schepers/MJK/a ... xx_ill.txt

https://www.pagetable.com/?p=39
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