Intel introduced the primary commercially profitable microprocessor, the 4004, in late 1971. By 1974 Intel had launched 4 microprocessors: the 4-bit, “low-end” 4004 and the upgraded 4040, and the 8-bit 8008 and 8080. Intel’s 4-bit 4004 and 4040 microprocessors had been used primarily for embedded management purposes the place I/O capabilities and efficiency and decrease half price outweighed the superior processing efficiency of 8-bit gadgets. Nonetheless, Intel not had the microprocessor market to itself. A number of different semiconductor distributors had launched competing microprocessors by 1974, notably the 4-bit Rockwell PPS4, the 8-bit Motorola 6800, the multichip Fairchild F8, and Nationwide Semiconductor’s 16-bit, multichip IMP-16. Toshiba had designed, constructed, and delivered the 12-bit TLCS-12 microprocessor particularly as an engine controller for Ford, and plenty of extra microprocessors had been on the way in which.
Even worse, the 4-bit TMS1000 microcontroller household, launched by Texas Devices (TI) in 1974, put a 4-bit CPU, RAM, ROM, and I/O circuitry on one chip, which simplified system design and lower the price of processor-based management considerably. The introduction of TI’s TMS1000 household actually acquired the eye of a number of potential prospects (and a number of other semiconductor makers). Intel, underneath siege, was beginning to lose embedded system designs to microprocessor and microcontroller opponents within the embedded market. That needed to cease. Intel wanted to reply, and the corporate knew it.
When Henry Blume Jr. arrived at Intel in October 1974, there was already an inner settlement that the corporate would develop a microcontroller. Intel was already making microprocessors, RAM chips, ROMs, and UV-erasable EPROMs and had the method applied sciences to make these components in home. The primary determination but to be made was whether or not the microcontroller would have a 4-bit CPU, just like the TMS1000, or an 8-bit CPU. Based on an oral historical past panel performed by the Laptop Historical past Museum (CHM) in 2008 with lots of the folks answerable for growing the 8048, Ed Gelbach, Intel’s Senior Vice President of Company Advertising, made the choice. Intel’s microcontroller would have an 8-bit CPU as a result of a 4-bit CPU didn’t have sufficient intercourse attraction. (Notice: The 8048 oral historical past within the reference part incorporates a number of references to intercourse attraction, not in a sexual context, which appears to have been used as a frequent determine of benefit at Intel throughout these occasions.)
Though the 8048 is the generic title that’s historically used for Intel’s first microcontroller – the precise household title is MCS-48 – the oral historical past makes it clear that the 8748 EPROM model appeared first. That’s as a result of the 8748 might be used instantly for software program growth and early prototyping and it could take a yr or two for patrons to develop their software program to the purpose the place they may order ROM-based 8048 gadgets. The 8748 would even be a harder system to fabricate as a result of Intel’s EPROM course of expertise was fairly totally different from the corporate’s different course of applied sciences, so it made sense to have that system prepared first, after which take the following yr to design the ROM-based 8048. Lastly, Intel may and would cost much more cash for a reusable 8748, which meant the corporate may accumulate extra income, sooner.
David Stamm joined Intel in January 1974, and initially labored on fixing bugs with the 4004 and 4040 microprocessors, which had been in manufacturing on the time. He then designed the Intel 4308, a assist chip for the Intel 4040 that mixed a 1-Kbyte ROM with some I/O ports. The 4308 mixed the features of 4 Intel 4001 chips that mixed a 256-bit ROM with an I/O port, so the 4308 contained about half a microcontroller, missing a CPU and RAM. After designing the 4308, Stamm was assigned to the 8048 challenge. He states within the 8048 oral historical past that he was single on the time and so he “lived and breathed the 8048 for two-plus years, night time and day.”
Stamm’s first accountability was to develop the microcontroller’s instruction set. It could be all new, to swimsuit an 8-bit microcontroller as an alternative of the microprocessors that Intel was already making. Within the oral historical past, Stamm remembers:
“There have been three of us who had been full-time on the challenge: myself, I used to be answerable for the instruction set and the logic design and the general chip schedule; David Buddy, who was answerable for the advanced duties related to integrating the EPROM expertise and all the EPROM programming logic and the sensing logic for the EPROM elements, in addition to a lot of the circuit design; after which Dwayne Hook who was answerable for all the structure of the chip…
“The primary section was actually the instruction set design. So right here I’m, I’m out of faculty a yr, had a Bachelor’s diploma, pondering to myself what enterprise do I’ve growing the following technology instruction set for these elements? And actually, no person was trying that fastidiously over my shoulder, however I stated, okay, high quality I’ll go for it. Fortunately, in school I had taken meeting language programming in a language referred to as COMPASS, which was a part of CDC, which is not any extra.
“However I realized loads about meeting language programming there, after which I’d labored on the 4040 and I checked out all the opposite instruction units with a view to attempt to provide you with what sort of instruction set would possibly make sense. The problem was [that] you needed to think about the instruction set by way of how a lot complexity in die-cost it could be.
“So, for instance, subtractions and compares can be actually helpful directions, however they added dramatically in further chip space. So, I made a decision we actually couldn’t afford these, particularly since we had been going to enter an 8-bit design. I had been a giant proponent of 8-bit. One of many counter arguments was price and die-size. So, throughout these design steps I did every part I may to jettison options and features that I assumed was going so as to add further die-size. Trying again at it now, I believe I most likely went a bit overboard — though on the time it could’ve been troublesome to have made that conclusion.”
At one level within the oral historical past, Blume interjects:
“I additionally wish to level out Dave’s two well-known – or his favourite directions had been SEX and SIN, which stood for set exterior mode and set inner mode. After which when the folks in programs took over, they eliminated SEX and SIN… they renamed them.”
Limitations within the 8048’s design, made to make sure that the chip might be manufactured with the accessible course of expertise, weren’t restricted to the instruction set. Reminiscence-space limitations had been one other essential restriction. The unique 8048 had a 4-Kbyte tackle house restrict for program reminiscence, but it surely was actually break up into two 2-Kbyte banks. The 8048’s program counter ostensibly had 12 bits, however probably the most vital bit got here from a separate register that might be used for financial institution switching. Initially, the 8048 included a 1-Kbyte program reminiscence, so this determination didn’t pinch at first. Finally, it could. Stamm explains, “…there have been heaps and plenty of limitations that existed, primarily with a view to hold the die-size down.”
Intel had no simulation software program in these early days, so the design workforce constructed a breadboard as an alternative. Stamm remembers:
“So, we constructed this huge breadboard, which in and of itself was but an entire different design challenge, utilizing the identical sort of combinatorial logic that we had been hoping to get rid of by means of the event of the 8048… we had been utilizing TTL and DTL gadgets, and the breadboard was enormous as I recall. It was most likely 5 foot tall by two or three ft huge, simply fully coated with wiring on the again.”
Such was the cutting-edge for chip design in these days.
Earlier than releasing the brand new microcontroller to manufacturing, the design workforce needed to meet with the Intel executives – Andy Grove, Gordon Moore, and Lex Vadasz – and persuade them that the 8748 was able to enter the market. A demo was so as, and Stamm determined to jot down a blackjack program. Stamm beloved to gamble and frequented Lake Tahoe casinos. The programmed 8748 would drive a dumb terminal, presumably by means of an RS-232 voltage translator. Stamm remembers that he found the restrictions of his personal microcontroller instruction set whereas writing the blackjack program. He additionally stuffed the 8748’s program reminiscence and didn’t have room so as to add a double-down characteristic to the blackjack recreation. The very first utility program written for the 8048 instantly introduced its fundamental limitations to mild.
So as to add intercourse attraction to the demo, the workforce determined to energy the 8748 with a battery constituted of strips of copper and zinc caught right into a lemon or an orange. At the least that’s the way it’s described within the oral historical past. The 8748 wants 5 volts at 100 milliamps to run, and a copper-zinc battery constituted of one orange generates a volt or much less, so both multiple orange was used to energy this demo or the story is apocryphal. It’s an awesome story although.
Intel introduced the MCS-48 microcontroller household, which included the 8048 and 8748, in late 1976, with the aim of transport 1000 income models, all 8748 gadgets, within the first quarter of 1977. Blume remembers that the precise variety of income models shipped was 770, which everybody thought-about a hit and is little question the results of a whole lot of pre-selling. The Intel 8748 was successful. Product supervisor Howard Raphael remembers early prospects together with Gilbarco (gasoline pumps), Tektronix, and Chrysler.
Magnavox based mostly its Odyssey2 online game console on an 8048. The 8048 was used extensively to energy quite a lot of analog music synthesizer keyboards together with the Korg Trident sequence, the Korg Poly-61, the Roland Jupiter-4, and the Roland ProMars.
Like many analog music synthesizers, the Roland Jupiter-4 used an Intel 8048 as a controller. Picture credit score: Raymangold22, Wikimedia Commons
The Sinclair QL private pc used an Intel 8049 (an 8048 with a 2-Kbyte ROM) to handle its keyboard, joystick ports, RS-232 inputs, and audio output. Nintendo used the ROM-less 8035 microcontroller (fairly presumably an 8748 with a foul EPROM) in its authentic Donkey Kong arcade recreation to generate the sport’s music. My good friend and colleague Wally Wahlen included an Intel 8048 as a controller into his design of the Hewlett-Packard 9876 thermal web page printer, which was launched in 1979.
Nintendo used an 8035 (a ROM-less 8048) to generate music in its Donkey Kong online game arcade console. Picture credit score: Rob Boudon, New York Metropolis, USA, Wikimedia Commons
Finally, the IBM PC would use an Intel 8048 as a keyboard controller. Nonetheless, the IBM PC was not the primary pc to make use of the 8048 this manner. That milestone belongs to the Tandy TRS-80 Mannequin II, which used a cost-reduced, 28-pin model of the 8048 referred to as the 8021 to handle its removable keyboard and scan the keys.
The Tandy Mannequin II private pc used an 8048 as a keyboard controller. Picture credit score: Piergiovanna Grossi, Wikimedia Commons
The Intel 8048 household turned an enormous success for Intel, however its design limitations surfaced virtually instantly. The limitation on program tackle house started to noticeably pinch prospects by 1977, and, by the fourth quarter of that yr, only a yr after its introduction, Intel began to outline the 8048’s successor, which might be referred to as the 8051. It could develop into a good larger success and will simply be referred to as the microcontroller that will not die, a minimum of not but. Nonetheless, that story should wait its flip.
References
Oral Historical past Panel on the Growth and Promotion of the Intel 8048 Microcontroller, Laptop Historical past Museum, July 30, 2008
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