Talk:MCS-51

message: Give the large commercial impact this chip had, it seems that a paragraph or section on the history, release dates, roll-out, early products, historical sales figures , etc would be useful.  Anybody know this??  — Preceding unsigned comment added by 204.128.192.31 (talk) 18:00, 11 February 2015 (UTC)
thread_title:  History/market Impact

message: How is it possible to adress 64k each of RAM and ROM (that would equal 128k in total) with a 16 bit adress bus? Is there a line on the control bus or something to with a simple bank-switch kind of thing? Wilsonsamm (talk) 20:08, 2 October 2008 (UTC)
thread_title:  64k of memory, eh? 

message: Is 8051 a CISC or RISC machine? Is 8051 a Harvard architecture?
—The preceding unsigned comment was added by 61.17.44.86 (talk) 08:05, 29 January 2007 (UTC)
replies: text: The use of register windows and the large register space (called, in the article, "IRAM") are RISC features and are atypical for microcontroller CPU's (e.g. 6809 or 68HC11) or desktop CPU's (e.g. the 68x00 or 80x86). The IRAM space is mostly, but not wholly a bona fide register space. Unary operations can typically be done directly on or with IRAM registers as well as the accumulator A. Binary register-to-register operations usually require A to be one of the registers, but the "mov" operation can be done directly IRAM to IRAM. Binary operations with constants, like unary operations, can generally be done directly with IRAM as much as they can with the accumulator A.  — Preceding unsigned comment added by 65.29.226.169 (talk) 05:45, 26 March 2023 (UTC)

text: At least with the ROM based variants, the original 8051 could be considered Harvard (and was described as such in the microprocessors course I took in college) in that you could not read from the program address space with normal data read instructions.  It was its own address space, and one presumes there was a separate, dedicated path for program fetches.  There are special "table lookup" instructions that allow you to read data from the program space, though.  Also, on external fetches, the original 8051 CPU would indicate whether it was fetching program or data, so you could continue to keep those address spaces separate even for external memory.  That said, once accesses go over the external bus, program and data busses are merged and so are no longer separate busses, and so it does look von Neumann-ish at that point.  If a given design ignores the program/data indicator, the two address spaces merge for those external fetches, like in any other von Neumann-style architecture.  Note that I limit my comments to the original 8051.  I haven't used any of the modern variants so I cannot comment on them. --Mr z (talk) 07:03, 3 September 2008 (UTC)

text: The CPU sees the code and data spaces as separate, with the former only accessed via "MOVC" (read-only), the latter via "MOVX" (read or write). Separate signalling are involved for these operations - which is the defining condition for the Harvard architecture, in contrast to the von Neumann architecture. It is entirely possible for the CPU to be wired into a mother board in a way that routes the external code space to the same physical device as the external data space, and it is a common configuration, though not optimal. Nonetheless, as far as the CPU is concerned, "MOVC" and "MOVX" access different memory spaces.  — Preceding unsigned comment added by 65.29.226.169 (talk) 05:53, 26 March 2023 (UTC)
thread_title:  8051 architecture 

message: I heard a rumor that the 8051 has somehow fallen into the public domain.
Is that true? If so, this processor should be listed at open hardware#CPU.
Or is Intel still selling the 8051 design under NDA licenses, even though it no longer fabs the chip?
Something like ARM Holdings sells CPU designs but does not fab any chips?
--68.0.124.33 (talk) 14:13, 13 August 2009 (UTC)
thread_title:  license 

message: Could we start listing various versions and manufacturers here somehow? A few have wp pages and links lead here but there's no line back to specific/super/modern versions. —Preceding unsigned comment added by Blades (talk • contribs) 12:43, 22 October 2009
:I don't think that such details are desirable in an encyclopedia article. Lists of such details seem to me to be contrary to the general spirit of several sections of Wikipedia:What Wikipedia is not, even though, as far as I know, this particular case is not explicitly mentioned there. JamesBWatson (talk) 14:05, 24 October 2009 (UTC)
thread_title:  Various versions 

message: The discussion of the memory architecture could use a little more detail. There is direct RAM, indirect RAM, SFR's, external RAM, and program memory, plus the bit-addressable feature of part of the RAM and some of the SFR's. I will add a section to the article in the near future, as it seems important to understanding the architecture. Pfagerburg (talk) 05:06, 13 November 2009 (UTC)
replies: text: Done. Community feedback will be greatly welcomed. Pfagerburg (talk) 04:03, 14 November 2009 (UTC)
thread_title:  Memory architecture 

message: I was trying to add in links to vendors who are currently providing enhanced 8051 parts. However, it was been consistently removed. I'm not sure why. Hope there is no problem placing the info here and it won't get removed again. The objective of the info is to allow anyone reading the article to be able to go further to actual devices.
*Atmel 8051 Architecture MCUs
*Cypress PSoC 3, some USB controllers uses enhanced 8051
*Infineon 8-bit MCUs are 8051 compatible
*Maxim 8051 drop-in MCUs
*Nuvoton 8-bit MCUs
*NXP 80C51 MCUs
*RAMTRON MCUs
*Silicon Labs MCUs
*SST FlashFlex MCUs
*Keil maintains a comprehensive device list database (It is mixed with ARM MCUs)
By the way, strangely the link on "Intel bows out, discontinues MCS-51" never get removed as if it is such an important info. —Preceding unsigned comment added 00:07, 31 August 2010 (UTC)
replies: text: Links to vendors is spam and will be reverted. So keep away ... --JWBE (talk) 19:40, 4 September 2010 (UTC)
thread_title:  Links to vendors 

message: This article claims that "The Intel MCS-51 ... has today largely been superseded by a vast range of faster and/or functionally enhanced 8051-compatible devices".
That seems ambiguous to me.
Is it saying that "8051-compatible devices" are so much better than the original "Intel MCS-51" that they made it obsolete -- i.e., that there is some technical difference between them, but perhaps not a big enough difference to require two separate encyclopedia articles?
Or is there is no technical difference between "Intel MCS-51" and "8051-compatible devices" (the phrases are synonyms), and that sentence is merely pointing out that *early* chips in that line have been superseded by *later* chips in that line?
Could someone tweak this article to explicitly say one or the other?:
* The "8051-compatible" microcontrollers, whether from Intel or from some other company, use the Intel MCS-51 instruction set.
* The "8051-compatible" microcontrollers, from Intel and from other companies, are very similar to the original "Intel MCS-51" series, except with these advantages ...
--68.0.124.33 (talk) 17:43, 12 January 2011 (UTC)
thread_title:  8051 vs MCS-51 

message: The Boolean logic engine is not new, it was included in the original chip.  NOte that it only operates on select registers and select RAM locations - it sure would be nice if everything was bit addressable...  The Rn banks no not change the interrupt latency which is defined as X number of clock before vectoring to the ISR code.  Instead, they speed up the ISR by facilitating fast register saving.Armstrong1113149 (talk) 23:02, 25 August 2011 (UTC)
thread_title:  Minor edits 

message: In "Important features and applications" the article states:
:Enhanced 8051 cores are now commonly used which run at six, four, two, or even one clock per machine cycle, and have clock frequencies of up to 100 MHz, and are thus capable of an even greater number of instructions per second
In "Use as intellectual property" the article states:
:In contrast, enhanced 8051 silicon IP cores now run at one clock cycle per machine cycle, and have clock frequencies of up to 450 MHz
Can someone find out how fast these actually run at?
--Maslen (talk) 03:55, 7 November 2011 (UTC)
thread_title:  Max CPU Frequency 

message: There is a discussion underway at Wikipedia talk:WikiProject Electronics#8031/8051: 1-bit architecture?  related to Tagremover's edits on this page, including a strong dispute of his/her interpretation. I would like to keep the discussion in one place rather than fragmenting it over multiple talk pages. --Guy Macon (talk) 14:31, 9 May 2013 (UTC)
thread_title:  8031/8051: 1-bit architecture? 

message: :The following is a closed discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review after discussing it on the closer's talk page. No further edits should be made to this discussion. 
The result of the move request was: not moved. (non-admin closure) ~ Aseleste (t, e | c, l) 15:04, 30 March 2021 (UTC)
replies: text: Intel 8051 →  – The name "8051" is usually used without prefixing it with Intel, and as 8051 is already a redirect this could be moved. Although it is orignally designed by Intel, the chip is no longer manufactured by them. WP:COMMONNAME supports using the most common name. PhotographyEdits PhotographyEdits (talk) 14:45, 23 March 2021 (UTC)

text: All other processor articles on Wikipedia use '<Manufacturer> <CPU name>'. e.g.: MOS Technology 6502, Motorola 68000, Intel 8086. I think it's good as 'Intel 8051'. -drt1245 (talk) 16:01, 23 March 2021 (UTC)
replies: text: That doesn't mean it should be the title. It is already a WP:PRIMARYREDIRECT, so it is already positioned as the WP:PRIMARYTOPIC for the term. — BarrelProof (talk) 16:10, 24 March 2021 (UTC)
thread_title:  Requested move 23 March 2021 

message: Hi, in retrospect I should have come to talk first before making this edit, although I still feel it is justified. After reading the datasheet referenced I couldn't immediately see a way to salvage the given statements. The flags that caught my attention for deletion were, "suggest that it has", "This also might explain", "also seems to indicate", "it may need", "This implies", "it might", "The speed suggests that", "appears to".
I'm aware some of this may in fact be true, but the datasheet does not give enough information to back it up, in addition the phrasing essentially says "I am just guessing." I welcome extra scrutiny of my edit, thanks Strangerpete (talk) 14:05, 8 January 2022 (UTC)
thread_title:  Microarchitecture edit 

message: Correct me if i am wrong but this article seams to say that MCS-51 is 'commonly termed 8051' supported by the move in this edit https://en.wikipedia.org/w/index.php?title=Intel_MCS-51&oldid=1013577791 for 'common title'. The intel 8051 is just one of the chips in the MCS-51 family.
This article has lots of parts that say 8051 architecture so this page is clearly about the MCS-51 family and is an anomaly Intel MCS-48 is another sires of microcontrollers from intel, and it is uses the family name with the individual chips as sub articles.
I suggest that either this article should be moved to Intel MCS-51 or split into two articles, one about the intel 8051 and one about the MCS-51 family. Uneverstop learning (talk) 08:10, 26 August 2023 (UTC)
thread_title:  Move to Intel MCS-51? 

message: :The following is a closed discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review after discussing it on the closer's talk page. No further edits should be made to this discussion.
The result of the move request was: page moved. Move history seemed trivial, so was not restored.  Arbitrarily0 (talk) 02:57, 28 October 2023 (UTC)
replies: text: Intel 8051 →  – This article seams to say that MCS-51 is 'commonly termed 8051' supported by the move in this edit https://en.wikipedia.org/w/index.php?title=Intel_MCS-51&oldid=1013577791 for 'common title'. The Intel 8051 is just one of the chips in the MCS-51 family.
This article has lots of parts that say 8051 architecture so this page is clearly about the MCS-51 family and is an anomaly Intel MCS-48 is another series of microcontrollers from intel, and it uses the family name with the individual chips as sub articles.
I suggest that either this article should be moved to Intel MCS-51 or split into two articles, one about the intel 8051 and one about the MCS-51 family. Uneverstop learning (talk) 22:19, 20 October 2023 (UTC)

text: My read is we've already established consensus for the move in the section immediately above so this can now be treated as an uncontroversial move. We still need an admin to do the move since there is non-trivial history to deal with at MCS-51. If my read is correct, I could submit a request at Wikipedia:Requested_moves#Uncontroversial_technical_requests. ~Kvng (talk) 16:56, 24 October 2023 (UTC)
thread_title:  Requested move 20 October 2023