Talk:Intel MCS-48

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This article is based on material taken from the Free On-line Dictionary of Computing prior to 1 November 2008 and incorporated under the "relicensing" terms of the GFDL, version 1.3 or later.

8048 Oral Panel

Interview with 8048 designers. Is the link worthwhile enough to be included in the 8048 page? http://www.computerhistory.org/collections/accession/102658328 I leave the decision to wikipedia maintainers (this note added 2010-01-16) http://archive.computerhistory.org/resources/text/Oral_History/Intel_8048/102658328.05.01.pdf

8048 the 1st µC?

Was it really _the_first_ microcontroller? Are the ROM and RAM both on-chip?--Anonymous

Thanks for the highly relevant questions. The 8048 was Intel's first µC but the TMS 1000 is reported to have been the first µC as such. And the ROM was in fact external; this is now corrected in the article. --Wernher 16:15, 5 Apr 2004 (UTC)

8049's internal ROM

To my best knownledge the 8049 DOES have internal ROM, consult the relevant Intel device datasheets if you don't believe me (note that IBM AT Keyboards manufacturered before 1996 usually have this MCU, and i have never encountered a KB with ROM on-board :-D :lol:) -- BKiL 19:41, 12 Nov 2004 (UTC)

Device  Internal     Memory
8035AHL none         64 x 8 RAM
8039AHL none        128 x 8 RAM
8040AHL none        256 x 8 RAM
8048AH  1K x 8 ROM   64 x 8 RAM
8049AH  2K x 8 ROM  128 x 8 RAM
8050AH  4K x 8 ROM  256 x 8 RAM
P8748H  1K x 8 PROM  64 x 8 RAM
P8749H  2K x 8 PROM 128 x 8 RAM

*note:  PROM = Programmable ROM

Thanks for the table; I guess we'll have to fix the article (again) then... :-) --Wernher 21:34, 12 Nov 2004 (UTC)

According to the IBM documentation for the original PC (available from the Retrocomputing Archive - http://www.retroarchive.org/dos/docs/ - the original IBM PC keyboards actually have an 8048 in them for generating the scan-codes. -- Dshadowwolf (talk) 04:45, 25 March 2009 (UTC)[reply]

Table added --JWBE (talk) 16:31, 4 September 2010 (UTC)[reply]

EPROM??

Arnim, are you sure they had EPROM? I am aware of manufacturers selling EPROM ICs as OTP PROM to save packaging costs, but the datasheet I had didn't mention anything about UV lignt, nor EPROM! Of course they _could_ have made enhanced versions since, but this would require us to make note of this fact, wouldn't it? Like the original i8051 had external ROM, but a (much) later clone named AT89C2051 had Flash. -- BKiL 22:03, 26 Dec 2004 (UTC)

Yes, there is one with EPROM. I took a picture of one a put it on the page. - Bryce

Haven't checked back for quite a while, sorry. Just for completeness, now that Bryce posted the picture: Intel (and others) manufactured the 8749 with EPROM in ceramic packages with UV window. I have several of these 8748/8749 (both Intel and NEC) floating around here. Intel also documented this capability in their data sheet(s). Nevertheless, it is possible that there are variants with OTP EPROM or even "real" PROM. I agree that PROM should be mentioned if we have information about such devices. - Arnim

Finally found a datasheet which mentions an 8648 with "One-Time Factory Programmable EPROM". I had a 8648 for years but never had a clue what it might be. Interesting to see that it has a ceramic package with UV window [1]. Unfortunately, the datasheet does not tell anything more about this one, the above description is all I have.: My understanding is that it was used like an 8048 by the customer but Intel programmed the OTP EPROM before delivery. Why this when there's an 8748? Maybe they intended to stock blank chips and quickly provide 8048-like samples. Fabricated 8048 always contain the ROM mask thus being specific for the customer (in contrast to "general purpose" 8648). - Arnim

Further Derivatives

The hunt for the PROM version revealed information about other derivatives. The updated table contains additional UPIs. -- Arnim

Device  Internal           Memory       Remarks
8021    1K x 8 ROM         64 x 8 RAM   Subset of 8048, 28 pins
8041    1K x 8 ROM         64 x 8 RAM   Universal Peripheral Interface (UPI)
8041AH  1K x 8 ROM        128 x 8 RAM   UPI
8741A   1K x 8 EPROM       64 x 8 RAM   UPI, EPROM version of 8041
8741AH  1K x 8 OTP EPROM  128 x 8 RAM   UPI, OTP EPROM version of 8041AH
8042AH  2K x 8 ROM        256 x 8 RAM   UPI
8742    2K x 8 EPROM      128 x 8 RAM   UPI, EPROM version
8742AH  2K x 8 OTP EPROM  256 x 8 RAM   UPI, OTP EPROM version of 8042AH
8648    1k x 8 OTP EPROM   64 x 8 RAM   Factory OTP EPROM

Table added --JWBE (talk) 16:31, 4 September 2010 (UTC)[reply]

"OTP EPROM"?

This seems like very odd language - an EPROM that can actually only be programmed once screams "PROM" to me. Unless we're getting our acronyms mixed up, it's electronically programmable, and someone's therefore knocked out the second E ("erasable") of EEPROM rather than the first?

Given the discussion above, does anyone mind if I'm "bold" and just change that? If the Intel spec sheets actually do say "OTP EPROM" then feel free to revert it... 91.125.59.216 (talk) 11:05, 16 March 2014 (UTC)[reply]

You're right, the "OTP" makes the EPROM a "PROM" (but it's not derived from an EEPROM, but rather from an UV-erasable EPROM). The term "OTP EPROM" provides more information than just PROM, because there's many technical variants of a PROM (e.g. bipolar fusable...). Here we're talking about an EPROM (which could be erased optically!), but since it does not have an opaque window, the UV-light could not reach the memory cell. Hence it's an "OTP". --Wosch21149 (talk) 10:14, 17 March 2014 (UTC)[reply]

Contribution: gezzus.thx@gmail.com

OTP = One Time programable's are a form of mask programmable rom that are written one time and cannot be written again.

OTP's use byte width fusible links (8 fuse links per byte per memory location) which are blown "open to create logic "0" and unblown to maintain a logic "1", these are known More commonly as PROMS and were the earliest form of permanent code/data storage for micro controllers & microprocessors until UV erased memory devices called eproms came along in the mid 1970's and remained the standard for programmable devices up till the early 1990's.

At which time a newer memory device type called EEPROM that used electrical current to both program and erase a memory device instead of UV light. these devices gave birth to what we see today Serial EEPROM & Serial Flash memories etc — Preceding unsigned comment added by 24.36.18.57 (talk) 08:10, 25 February 2015 (UTC)[reply]

MIPS?

MIPS usually refers to performance relative to a VAX 11/780 not literal instructions, and most instructions don't execute in one cycle anyway. 24.93.185.231 (talk) 01:43, 23 May 2017 (UTC)[reply]

8242

@Stepho-wrs: The Intel datasheet (page 2) lists the 8242 as a version of the 8042 but preprogrammed with keyboard controller firmware. Drahtlos (talk) 01:33, 19 July 2022 (UTC)[reply]

Hmm, looks like you are right. Strange for Intel to be selling it with someone else's software inside it but there it is. Stepho talk 22:55, 19 July 2022 (UTC)[reply]

Synthesisers

Regarding this: "The 8048 was used in the Magnavox Odyssey² video game console, the Korg Trident series,[8] and the Korg Poly-61,[9] Roland Jupiter-4 and Roland ProMars[10] analog synthesizers."

Certainly the Jupiter-4, judging by its service notes, used NEC's μPD8048. Judging by the numbers and specs of the μPD8048, μPD8748, and μPD8035L, they're very likely MCS-48 series clones. (NEC's data sheets don't mention Intel by name, but do mention "compatability with the industry standard 8048".) I haven't checked the others, but it wouldn't surprise me if Japanese companies were pretty routinely using the NEC clones rather than the Intel originals.

ZoeB (talk) 14:52, 9 July 2023 (UTC)[reply]

Alternative names

ToaneeM and I are having a MOS:BOLDSYN disagreement. I'm not sure what I've misinterpreted but this article also covers specific members of the family. They are mentioned in the lead and these terms redirect to this article. Per MOS:BOLDSYN the should appear in bold in the lead. The terms in dispute: 8048, 8035, 8748. ~Kvng (talk) 14:08, 30 August 2023 (UTC)[reply]

Kvng I'm afraid I'm a bit confused as to where you're confused. The article text correctly says about the MCS-48 series, "its first members were 8048, 8035 and 8748". 8048, 8035 and 8748 are not alternative names for the MCS-48 family, they're just members or it. 8035 is a component, one without program memory. 8748 is a different component, one with EPROM. MOS:BOLDSYN states "Only the first occurrence of the title and significant alternative names are placed in bold" (emphasis theirs). So the article text is fine as it stands and the alteration is incorrect for MOS:BOLDSYN. My change comments noted that.--ToaneeM (talk) 15:30, 30 August 2023 (UTC)[reply]

Articles like this are about multiple topics; in this case the processor family and the individual processors in the family. A reader searching for "8048" will be redirected to this article and may be confused that the title of the article is different from what they searched for. The purpose of the bolded text in the lead is to orient the reader and avoid unnecessary WP:ASTONISHMENT. See WP:RPLA. ~Kvng (talk) 15:50, 30 August 2023 (UTC)[reply]

Kvng, Ahh. First off, I failed to check if 8048, 8035, 8748 and 8049 redirect to this page, so apologies there as your explanation makes sense now. I've reinstated your first edit with a change note explaining why. Secondly, I'm afraid it didn't help much that you putting change notes of just (bold redirects) then of (MOS:BOLDSYN) on your two edits. More detail on either edit note would have helped understanding and saved us both some time. And third, thanks very much for a friendly and reasoned exchange. It's appreciated and sped us to a good resolution for us and the site.--ToaneeM (talk) 18:20, 30 August 2023 (UTC)[reply]

Sorry that my edit summaries were too terse in this case. I don't think I'm as bad as some of these suggestions. Happy editing! ~Kvng (talk) 22:07, 30 August 2023 (UTC)[reply]

Original IBM PC?

I think this is wrong. I believe the original IBM 5150 used discrete logic for its keyboard.

The citation is not available online, but the fact that it's from 1984 makes me strongly suspect this is referring to the AT not the original IBM PC.

Unless someone has a cite to the contrary, I'm going to delete this 2600:1702:890:73F0:B1E2:E3E2:90BB:5B67 (talk) 00:42, 30 June 2024 (UTC)[reply]

Just because a document is not online does not make it an invalid reference. (I did find the referenced document online, though.) The IBM PC was made until 1987, making a 1984 data book revision quite plausible. You need to read the ref'd document before deleting this item. The 5150 had a detachable keyboard with a serial interface, which would make it a clumsy design in the absence of a microcontroller. The use of the 8048 seems to be confirmed by multiple sources. RastaKins (talk) 13:32, 30 June 2024 (UTC)[reply]

I got curious about this and did some research. https://github.com/tmk/tmk_keyboard/wiki/IBM-PC-XT-Keyboard-Protocol (which is not a valid reference for us but an excellent launching point to find other references) lists many of his own references. One of them is for IBM's technical manual for the XT: https://www.reenigne.org/crtc/PC-XT.pdf On page 148 it shows an 8048 in the XT keyboard schematic. Of course, the original 5150 might be different (the XT 5160 was the successor to the 5150) but I would consider it unlikely due to the complexity of designing custom logic to scan the keyboard and create serialise scan codes that allow for alt up/down, shift up/down, ctrl up/down scan codes compared to the ease of using the 8048. Stepho talk 22:23, 30 June 2024 (UTC)[reply]

The IBM PC 5150 Technical Reference Manual (1981) clearly states that the external keyboard contains an 8048 'microcomputer'. Leave the article text as it is, I'll add the references later today. ToaneeM (talk) 23:16, 30 June 2024 (UTC)[reply]

You're right. It's on 2-14 of the Technical Reference Manual. I was mistakenly looking at the Keyboard Interface Block Diagram on 2-15, but that's the system board not what's in the keyboard itself. 2600:1702:890:73F0:E91A:DC56:63F8:D405 (talk) 15:49, 1 July 2024 (UTC)[reply]