Talk:MOS Technology 6502/Archives/2015

Error about nature of MDT-650
''However, this left MOS with the problem of getting developers to try their processor, so Peddle designed the MDT-650 (for "microcomputer development terminal") single-board computer. Another group inside the company designed the KIM-1, which was sold semi-complete and could be turned into a usable system with the addition of a 3rd party computer terminal and compact cassette drive.''

The MDT-650 was NOT a single board computer. The following article appeared in the April 1976 issue of Microcomputer Digest (Vol 2 Num 10).


 * MICROCOMPUTER DEVELOPMENT TERMINAL
 * MOS Technology has announced the MDT650 Microcomputer Development Terminal for modeling new 650X designs. The MDT650 terminal is used to evaluate and debug the user's programs and system hardware. The unit can be configured to a wide range of designapplications through user-system emulation.
 * The MDT650 incorporates a completely separate processor and bus structure for application emulations, thus eliminating emulator executive overhead time during real time execution.
 * Interaction with the MDT650 is normally with the integral keyboard/display. However, a TTY or other terminal device can be used. The expandable port configurations are TTL compatible.
 * The standard MDT650 system allows the user to assign up to 65K of memory as desired (with independent address and data bases). The ROM resident system monitor includes all necessary functions for program loading, debugging, and execution. A resident assembler may be used to assemble machine instructions. Interpretation of machine codes is linked to original op-codes, labels and mnemonics. A resident editor provides source language editing capability.
 * The MDT650's bare system price of $3950 includes dual microprocessor module, RAM memory module, program trace and address trap board, I/O b~ard, resident monitor ROM module; chassis with 14 board slots, power supplies, cabinet, keyboard and display, system monitor, assembler text editor, user's manual, MCS650 assembly language programming manual, and MCS650 assembly language reference card.
 * Options planned include a PROM programmer available for 82S115, 2708 or 1702A, wirewrap board for custom designs, extender board module, address and data bus display board, 4K RAM board, 8K PROM board, 2K RAM/4K PROM board, I/O board, user RAM write protect option, high speed ports for printer, card readers, floppy disc interface, In-Circuit Emuiator, and system s6ftware source listings.
 * MOS Technology reports availability of the base system in the second quarter, 1976 with the various hardware options becoming available in the second and third quarters, 1976.
 * The standard MDT650 system allows the user to assign up to 65K of memory as desired (with independent address and data bases). The ROM resident system monitor includes all necessary functions for program loading, debugging, and execution. A resident assembler may be used to assemble machine instructions. Interpretation of machine codes is linked to original op-codes, labels and mnemonics. A resident editor provides source language editing capability.
 * The MDT650's bare system price of $3950 includes dual microprocessor module, RAM memory module, program trace and address trap board, I/O b~ard, resident monitor ROM module; chassis with 14 board slots, power supplies, cabinet, keyboard and display, system monitor, assembler text editor, user's manual, MCS650 assembly language programming manual, and MCS650 assembly language reference card.
 * Options planned include a PROM programmer available for 82S115, 2708 or 1702A, wirewrap board for custom designs, extender board module, address and data bus display board, 4K RAM board, 8K PROM board, 2K RAM/4K PROM board, I/O board, user RAM write protect option, high speed ports for printer, card readers, floppy disc interface, In-Circuit Emuiator, and system s6ftware source listings.
 * MOS Technology reports availability of the base system in the second quarter, 1976 with the various hardware options becoming available in the second and third quarters, 1976.
 * Options planned include a PROM programmer available for 82S115, 2708 or 1702A, wirewrap board for custom designs, extender board module, address and data bus display board, 4K RAM board, 8K PROM board, 2K RAM/4K PROM board, I/O board, user RAM write protect option, high speed ports for printer, card readers, floppy disc interface, In-Circuit Emuiator, and system s6ftware source listings.
 * MOS Technology reports availability of the base system in the second quarter, 1976 with the various hardware options becoming available in the second and third quarters, 1976.
 * MOS Technology reports availability of the base system in the second quarter, 1976 with the various hardware options becoming available in the second and third quarters, 1976.

Also, the MDT-650 was NOT designed by Peddle, as stated on Page 25 of "Commodore: A Company on the Edge", but by an outside firm by the name of Monolithic Systems. — Preceding unsigned comment added by 72.190.74.67 (talk) 14:29, 15 July 2012 (UTC)

Apple II accelerators
Every computer and microprocessor ever made was soon too slow for users. The 6502 was used in more applications than home computers and Apple was only one provider. I am unsure that the Apple II accelerators article deserves such a prominent link in the 6502 article. -- SWTPC6800 (talk) 17:35, 23 March 2015 (UTC)


 * Agreed, although some content regarding acceleration should remain in the article. Accelerator boards and drop-in chips were also fairly common for Commodore 8-bit systems. I'd suggest that we strike the Apple II specific text and "main article" link, while retaining the remaining text (copyedited as needed). // coldacid (talk&#124;contrib) 17:46, 23 March 2015 (UTC)

Seealso "For the year 6502"
wrote on my talk page:

Hi Jeh, I just reverted your good-faith edit of the redirect notice to the MOS Technology 6502 article. Since 6502 redirects to the article, it's best to leave in the notice for those few people who do come to the page expecting the year instead. // coldacid (talk&#124;contrib) 22:19, 23 March 2015 (UTC)


 * You don't really expect me to think you're serious, right? Can you think of any reason that someone might be looking for the specific year 6502? Let's see, is that year mentioned in the 7th millennium article? No. Again, per my original edit comment: Don't be ridiculous. Jeh (talk) 22:23, 23 March 2015 (UTC)


 * Just because something is very unlikely to happen doesn't mean it won't happen. There's no harm done in leaving the message there in the off chance that it does happen. And I'll thank you to be more civil in your responses and edit summaries. Please don't become the next Wtshymanski. // coldacid (talk&#124;contrib) 22:33, 23 March 2015 (UTC)


 * The harm IMO is exactly that it looks ridiculous and silly, and it may waste a reader's time. (Reader: "Why do they think anyone would be looking for the year 6502?" (clicks on the 7th Millennium link) "Nope, nothing special about that year. What a waste of time." And don't say "no one will do that"; that's what I did.)
 * So, it's not only ridiculous and silly, it's misleading, in that it implies that there is some significance to the year 6502, and that there is some mention of it in the 7th millennium article. For those who come here looking for the chip, I do not think that the value of serendipitously learning "nope, nothing interesting predicted for the year 6502" outweighs the waste of time or the annoyance. It devalues the article, and by extension, Wikipedia. We're trying to look credible here. The probability that anyone has any reason to look for the year 6502 may not be zero, but it would be indistinguishable from zero even in 128-bit floating point. Do we do this for 6800, 8080, 8086? No. (And please don't.) Would we do it for 2525, if there was a chip of that number? Yes, because there are at least two well-known cultural references to that year. Lacking such for 6502, this seealso should go. Jeh (talk) 22:52, 23 March 2015 (UTC)
 * From a June 2014 Intersil Data Sheet – "HA-2520, HA-2522, HA-2525 comprise a series of operational amplifiers delivering an unsurpassed combination of specifications for slew rate, bandwidth and settling time." If the 2525 op amp becomes as popular as the 741, it may get an article. - SWTPC6800 (talk) 00:47, 24 March 2015 (UTC)
 * I'd say "as popular as the 741" is a pretty high bar! Jeh (talk) 03:33, 24 March 2015 (UTC)

The link to the 7th millennium sounds like an April Fools' joke. It was added on March 13, 2015 by Georgia Guy. The User_talk:Georgia_guy page has several items about questionable  disambiguation  links -- SWTPC6800 (talk) 00:17, 26 March 2015 (UTC)
 * A little early, but it's possible. Since we've heard nothing from coldacid for two days, and I feel my previous point is definitive (and so far un-countered), I went ahead and re-deleted the seealso. Jeh (talk) 00:37, 26 March 2015 (UTC)
 * I support the removal. At first I thought it was a who care's issue, but I agree with your above comments that a link to 7th millennium at the top of this article is a waste of time: it has nothing to do with "6502". Johnuniq (talk) 00:41, 26 March 2015 (UTC)
 * After you went all off with your two-paragraph reply, I simply decided "fuck it" and not to bother further. // coldacid (talk&#124;contrib) 02:01, 26 March 2015 (UTC)

6502acme syntax highlighting lost
Since the switch from Geshi to Pygments for syntax highlighting (T85794), support for '6502acme' was unfortunately dropped, as can be seen with the plain text formatting on this page and any others. If you want specialised '6502acme' syntax highlight support again, it will need to be added to Pygments. I changed Interrupts in 65xx_processors to use 'asm', however a patch has been merged to map '6502acme' to use the 'asm' handler, which does the right thing as far as I can see. John Vandenberg (chat) 11:42, 12 July 2015 (UTC)

Dubious reference for "the original RISC processor"
There is a claim that "A Byte magazine article once referred to the 6502 as 'the original RISC processor' ". I could not find that article in the Byte magazine archives so I reviewed the history of MOS Technology 6502 on Wikipedia.

The 17 August 2006 version of the article had this addition to Instruction set features:


 * 6502 - the first RISC µP – With link to concise 6502 programming chart in PDF (Eric Clever).[]

On 12 November 2006 this was "reworded" and moved to the 6502 trivia section. 
 * A magazine article once referred to the 6502 as the original RISC processor, due to its efficient and simple instruction set and its 256 zero-page "registers." It is technically not a RISC design, however.

By 20 November 2006 it was changed to read:
 * A magazine article once referred to the 6502 as the original RISC processor, due to its efficient and simple instruction set, as well as its 256 zero-page "registers." It is technically not a RISC design, however, as it has a number of instructions that directly modify memory (e.g. ROR ), contrary to the basic "load/store" philosophy of real RISC processors.

On 20 February 2007 the paragraph was changed from "magazine" to "Byte Magazine".

The quote started on a personal web page and was promoted to Byte magazine.-- SWTPC6800 (talk) 23:37, 12 September 2015 (UTC)


 * The whole section appears to me to be problematic as it then goes on to describe all the ways in which the 6502 was not typical of ISAs. Personally I think the quasi-quote is just wrong; the PDP-8 is a much better candidate for "the first RISC processor". But that's beside the point. I would drop the opening sentence and change the tone of the whole paragraph to merely descriptive without passing much judgment on its RISCness. I would also suggest that it needs far more references. Jeh (talk) 23:42, 12 September 2015 (UTC)
 * Removing the RISC paragraph would probably be best. I think the original idea behind the RISC comment in Byte was that the 6502 was a single-chip processor (unlike PDPs) where it was largely possible to examine a binary opcode and deduce what it was going to do from fixed-width fields (with lots of exceptions). Regardless of how it was actually implemented, one could imagine CPU hardware executing opcodes with mostly standard logic gates and comparatively little complex microcode. My guess is that the current text in the article is the result of editors adding their analysis. Johnuniq (talk) 04:54, 13 September 2015 (UTC)

Internal clock or not?
Under the 6512 heading the article says, "...instead of using an internal clock generator like the 6502." Then later under Acceleration it says, "As the 6502 is externally clocked..." So, which is it? These statements seem to directly contradict one another. 66.225.134.125 (talk) 17:56, 21 December 2015 (UTC)