R65C02P4 fake chips
R65C02P4 fake chips
I purchased five of this ICs off eBay. This is what arrived: Manufacturing date 2019. On the top, Mexico, on the bottom, Taiwan and a handful of scratches.
I wouldn't mind much if they worked. I hooked them up on a breadboard, providing power (5V) and tying reset, IRQ, NMI and SO high by 1K resistors. 1 Mhz clock courtesy of my function generator and later by a crystal. Data bus set to EA by 1k resistors. Power consumption is about 30 mA.
This is what I'm observing on all ICs:
-Current raises to 250 mA when reset pin is grounded.
-No clock output on PHI1 and PHI2
-No activity on address or data bus. (I cached some on one specific address pin at one time, but gone after reset).
-Some address lines are high, others low and others sit in between.
I'm pretty sure they are dead. But that the same symptoms appear on all five makes me suspect that my setup is wrong. Any ideas?
Juan
I wouldn't mind much if they worked. I hooked them up on a breadboard, providing power (5V) and tying reset, IRQ, NMI and SO high by 1K resistors. 1 Mhz clock courtesy of my function generator and later by a crystal. Data bus set to EA by 1k resistors. Power consumption is about 30 mA.
This is what I'm observing on all ICs:
-Current raises to 250 mA when reset pin is grounded.
-No clock output on PHI1 and PHI2
-No activity on address or data bus. (I cached some on one specific address pin at one time, but gone after reset).
-Some address lines are high, others low and others sit in between.
I'm pretty sure they are dead. But that the same symptoms appear on all five makes me suspect that my setup is wrong. Any ideas?
Juan
Re: R65C02P4 fake chips
They could be a completely different chip, relabelled. If your time is precious, or your money, I'd recommend you reject them and get a refund.
But of course if you are curious, you might wonder what they really are.
But of course if you are curious, you might wonder what they really are.
Re: R65C02P4 fake chips
I ordered and received 5 very similar marked chips in late 2018. They arrived with 2019 date codes. All 5 chips seem to be nmos 6502 relabelled as cmos parts.
Re: R65C02P4 fake chips
I check some of the 40 pin chips I've acquired over the years, those reverse markings look a lot like those on an Atmel AT89C51 micro controller.
No a great photo, but hopefully you'll be able to see the similarity of the font, and the format of the text. which on my chip is 0C3206-19651L on the top row and 1-U 0C0045 on the lower
No a great photo, but hopefully you'll be able to see the similarity of the font, and the format of the text. which on my chip is 0C3206-19651L on the top row and 1-U 0C0045 on the lower
Re: R65C02P4 fake chips
In case it helps, here's a photo of a couple of P4s, a P3 and a P2 I bought last year.
Looks like the fakers are imitating the old '90s printing instead of using the new 21st century font?
None of my Rockwell chips (I have a couple of Ps, as well) have any markings on the bottom.
I've not yet tested any of these, though I can certainly wire up a NOP pullup/down and see what my oscilloscope says it's doing, if anybody's particularly concerned. (Or maybe even whack them into my Apple I replica if there's real doubt about whether or not they're CMOS parts.)
Looks like the fakers are imitating the old '90s printing instead of using the new 21st century font?
None of my Rockwell chips (I have a couple of Ps, as well) have any markings on the bottom.
I've not yet tested any of these, though I can certainly wire up a NOP pullup/down and see what my oscilloscope says it's doing, if anybody's particularly concerned. (Or maybe even whack them into my Apple I replica if there's real doubt about whether or not they're CMOS parts.)
Curt J. Sampson - github.com/0cjs
Re: R65C02P4 fake chips
(I've a feeling in previous discussions of this sort we've wondered whether you can figure out which pins are inputs and which outputs, as they have characteristic circuits inside. If the Is and Os don't match up to the expected pinout, it's certainly not what it claims to be.)
Re: R65C02P4 fake chips
RDY and BE are other pins you should tie high with resistors. But they shouldn't affect Phi1/Phi2 outputs.
- BitWise
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Re: R65C02P4 fake chips
Chromatix wrote:
RDY and BE are other pins you should tie high with resistors. But they shouldn't affect Phi1/Phi2 outputs.
Andrew Jacobs
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Re: R65C02P4 fake chips
BigEd wrote:
They could be a completely different chip, relabelled. If your time is precious, or your money, I'd recommend you reject them and get a refund.
But of course if you are curious, you might wonder what they really are.
But of course if you are curious, you might wonder what they really are.
I will try to get some 6502s from reputable suppliers, albeit more expensive. Or I could have another go at ebay's lottery...
Chromatix wrote:
RDY and BE are other pins you should tie high with resistors. But they shouldn't affect Phi1/Phi2 outputs.
Also both supposedly GND pins (1 and 21) are not connected internally, don't know if this would be expected, although I would suppose they should be.
cjs wrote:
I've not yet tested any of these, though I can certainly wire up a NOP pullup/down and see what my oscilloscope says it's doing, if anybody's particularly concerned. (Or maybe even whack them into my Apple I replica if there's real doubt about whether or not they're CMOS parts.)
By the way, the eBay seller I bought from was adeleparts2010.
Juan
Re: R65C02P4 fake chips
BitWise wrote:
Chromatix wrote:
RDY and BE are other pins you should tie high with resistors. But they shouldn't affect Phi1/Phi2 outputs.
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Re: R65C02P4 fake chips
Rockwell hasn't made 6502 products in many years—what you have are counterfeits. The only contemporary supplier of 65C02 microprocessors is WDC. Why do people go to eBay for something that can be gotten through a 100 percent legit source? Demand your money back and report the supplier for selling fake product.
x86? We ain't got no x86. We don't NEED no stinking x86!
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Re: R65C02P4 fake chips
It looks like the top of the chip has been sanded to remove the original markings, then printed with the Rockwell bits. Needless to say, I think they're just selling junk parts with markings for whatever they think they can sell.
I also agree with BDD.... why buy suspect old parts on eBay when you can buy new currently in production parts which are certainly much better with higher clock speeds, etc.?
I also agree with BDD.... why buy suspect old parts on eBay when you can buy new currently in production parts which are certainly much better with higher clock speeds, etc.?
Regards, KM
https://github.com/floobydust
https://github.com/floobydust
Re: R65C02P4 fake chips
BigDumbDinosaur wrote:
Rockwell hasn't made 6502 products in many years—what you have are counterfeits. The only contemporary supplier of 65C02 microprocessors is WDC.
Quote:
Why do people go to eBay for something that can be gotten through a 100 percent legit source?
Curt J. Sampson - github.com/0cjs
Re: R65C02P4 fake chips
BigDumbDinosaur wrote:
Rockwell hasn't made 6502 products in many years—what you have are counterfeits. The only contemporary supplier of 65C02 microprocessors is WDC. Why do people go to eBay for something that can be gotten through a 100 percent legit source?
@cjs: "I have a couple of parts with 2010 date codes on them"
Those are fakes (or at least the date is fake). Rockwell stopped existing in 2001.
Re: R65C02P4 fake chips
Tor wrote:
@cjs: "I have a couple of parts with 2010 date codes on them"
Those are fakes (or at least the date is fake). Rockwell stopped existing in 2001.
Those are fakes (or at least the date is fake). Rockwell stopped existing in 2001.
I guess it's possible that the R65C02P4 chips in my photo above were relabeled to a faster part number, so as to attract customers (they were about the same price as other vendors), but that hardly seems worth the effort.
On the other hand, the CPU in my Apple I replica is labeled, "R6502P 13500-13 MEXICO 1349 B50323-8 [Rockwell logo]." And it definitely works at least as far as the monitor, BASIC and my own minor hacking so far goes. What on earth that works reasonably well as a 6502 would you re-label as a 1 MHz NMOS part?
Curt J. Sampson - github.com/0cjs