Talk:MOS Technology 6502

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Primary source

A huge amount of the detail in the "History and Use" section comes from a primary source -- a YouTube video interview with Chuck Peddle. The Wiki policy on primary sources allows their use, but only sparingly; no synthesizing or interpretations based on those sources should be done, otherwise that strays into WP:OR territory. Since so much of this section relies on a single primary source, anyone who wants to work on this article should, instead of expanding it or adding more detail, try and find reliable secondary sources which can back up or correlate what was said in that interview, if possible. A lot of the detail in this section straddles the line between straightforward facts (which *can* use primary sources as citations) and analysis/interpretation of what Peddle is saying (which is *not* allowed). I don't feel the issue is so egregious as to warrant any removal of material right now, but I do think efforts on this article should be focused primarily on getting rid of the dependence on primary sources as much as possible.

I don't want to throw a bunch of tags in the article as that would make it look quite messy, so I decided to just post this here on the talk page instead. If I find time in the near future, I'll get to work on this. In the meantime I encourage anyone looking at working on this page to search carefully for quality secondary sources. MrAureliusR_Talk! 03:47, 1 December 2020 (UTC)

@MrAureliusR: I believe you are incorrectly interpreting why primary sources need to be examined carefully. The issue with primary sources is not simply who made them, but when they were made. The operational definition in this case is:

A primary source was a source that was created at about the same time as the event, regardless of the source's contents.

The concern is that someone writing about events that happened to them as they happened will not be an accurate reflection of those events or maybe deliberately obscuring them. The section on "How to classify a source" clearly spells this out.

Consider, for instance, if this was an article by Chuck when the 6502 was released and it contained statements like "Best processor ever!" In that case, one might be sceptical of its accuracy. But here we're talking about statements made decades later, surrounded by incredible historical detail, lacking any sign of obfuscation that I can see.

I do not see an attempt to examine this source critically, simply "primary bad". So do so, examine the source carefully. Do you see any reason to believe it is not an accurate account of the events, other than "primary bad"? If so, we have something to talk about. Maury Markowitz (talk) 14:21, 3 February 2021 (UTC)

The issue is that it's a YouTube video, which are discourages as sources (as far as I understand it) and also, it's just one person talking about their memory of events. There is no way to verify that what Chuck is saying is accurate. This is why secondary sources, which have researched & verified his statements, are so important. Anyone can say anything on any social media or video platform. I'm not doubting Chuck's integrity or memories; but having this entire section be based on *one person's account* of what happened over 35 years ago isn't exactly the shining definition of reliable sourcing. MrAureliusR_Talk! 19:26, 4 February 2021 (UTC)

Feel free to add more sources when you find them. Maury Markowitz (talk)

Section "Moving to NMOS" implies that the 6502's competitors were PMOS chips. Actually they were enhancement-load NMOS.

@Maury Markowitz: (Pinging Maury Markowitz because he wrote the text involved.) This whole section, describing some of the semiconductor advances in the 6502, implies that the 6502's competitors, including the Intel 8080 and Motorola 6800, were PMOS microprocessors. This is incorrect—both were NMOS chips. (Intel used PMOS for its 4004, 8008, and 4040.) The difference is that the 8080 and 6800 used enhancement-load NMOS rather than the depletion-load NMOS used in the 6502. The multiple voltages given, +12V, +5V, and -5V, are characteristic of enhancement-load NMOS rather than PMOS. Intel's PMOS chips used +5V and -10V.

I'm not doubting that MOS Technology's existing fabs were PMOS, by the way.

--Colin Douglas Howell (talk) 05:22, 3 February 2021 (UTC)

@Colin Douglas Howell: You are correct, the change was to depletion mode NMPS, which I have mentioned in the 6800 rewrites. I only came across this detail after making the edits to this article. However, I am not convinced that MOS used PMOS and hadn't already moved to non-depletion NMOS. Maury Markowitz (talk) 14:04, 3 February 2021 (UTC)

Number of transistors?

The article states (in the infobox) that the 6502 had 3510 transistors. This seems to hide an important detail:

"The 6502 chip is made up of 4528 transistors (3510 enhancement transistors and 1018 depletion pullup transistors)."

This is mentioned even in the references quoted, like this amazing work of art.

I think this should be mentioned in the infobox. They are transistors on the die, and therefore need to be mentioned in a count. However, they are not "logic transistors". Should this simply be noted on a separate line in the box? Maury Markowitz (talk) 11:44, 12 May 2021 (UTC)

Sales "in the 100's of millions" out of date

The article claims that the 65C02/65xx family continues to be widely used, with "with estimated production volumes in the hundreds of millions".

The linked reference is to the Western Design Centre website. The actual paragraph there says: "...Annual volumes in the hundreds (100's) of millions of units keep adding in a significant way to the estimated shipped volumes of five (5) to ten (10) billion units. With 200MHz+ 8-bit W65C02S and 100MHz+ 8/16-bit W65C816S processors coming on line in ASIC and FPGA forms, we see these annual volumes continuing for a long, long time. The 65xx brand is probably the only processor family that has remained loyal to its ISA over the last 33 years."

The last 33 years since 1975, start of the '65xx brand', means this was written in 2008, making it 14 years out of date.

That website redirects you to a newer WDC website, which contains a revised statement: "Through the last 30+ years as one of the most popular microprocessor architectures of all time the 65xx brand is estimated to have over six billion embedded 65xx processors shipped and is growing by hundreds of millions of units per year, provided by WDC and its licensees."

The relevant text on that page looks like a rehash of the original site's text. The '30+ years' looks like a rehash of the '33 years', aimed to make it timeless so they don't have to worry about changing the website. So it's also not proven to be current and is likely out of date.

All in all, there needs to be better evidence that the 65C02/65xx family sells these quantities per annum, either in parts or as licenced IP.

Or the statement's wrong and should be removed - not just removing the quantities but also the claim of popularity and any volumes.

Since this applies to the 65C02, I have posted this on the Talk page there also. I did that a week or so ago but had no replies. ToaneeM (talk) 18:57, 3 February 2022 (UTC)

Using the weak ref we have, I think it is safe and robust to say that billions of these processors have been shipped. Documenting a more exact number or shipments per year will need ongoing attention and is potentially WP:PROMO. ~Kvng (talk) 15:57, 7 February 2022 (UTC)

Instruction table layout

Should the instruction table have the rows 000xxx00 to 111xxx11 (approximately corresponding to instructions) and the columns xxx000xx to xxx111xx (approximately corresponding to addressing modes)? — Preceding unsigned comment added by Qalle2 (talk • contribs) 22:45, 12 February 2022 (UTC)

Perhaps something like this (updated link). -Qalle2 (talk) 02:03, 13 February 2022 (UTC)

That's an interesting table but it might only be valuable for hard-core 6502 people. The current table seems fine. Johnuniq (talk) 02:50, 13 February 2022 (UTC)

The Tamagotchi probably did not use a 6502

The Wikipedia page states that the Tamagotchi used a 6502 and links to someones blogpost claiming it uses a 6502 with no evidence. Many pages, such as http://tama.loociano.com/, claims the original Tamagotchi uses a CMOS E0C6S46, which is more likely given its specs with, among other things, a controller for a LCD. Bjanders (talk) 17:47, 15 December 2022 (UTC)

The original Tamagotchi (P1) used E0C6S46, but a later version ("Tama-Go"?) used a 6502-derived GPLB5X processor. [1] [2] Krótki (talk) 09:22, 23 December 2022 (UTC)