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)
- 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 . 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
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
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... 188.8.131.52 (talk) 11:05, 16 March 2014 (UTC)
- 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)
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 184.108.40.206 (talk) 08:10, 25 February 2015 (UTC)