Leaving Arizona – by Babbage

In Motorola’s Pioneering 6800 : Origins and Architecture, we noticed how a small staff, primarily based in Phoenix, Arizona, developed the Motorola 6800 microprocessor. The announcement of the 6800, in April 1974, meant that Motorola appeared to have a contender for early management in microprocessors. In comparison with its main 8-bit rival, the Intel 8080, the 6800 had a chic and clear instruction set and a design that was simpler to construct programs round.

The 6800 staff created a easy single-board pc (pictured above), with simply six built-in circuits, which they used to display the 6800 to Motorola’s senior administration. In accordance with Tom Bennett, who led the design of the 6800:

Chuck Peddle and John Buchanan wired up and put collectively and programmed it. And all it did was say: “Hello, John” or “Hello, Bob,” …

Bob was Bob Galvin, Motorola’s Chief Govt, son of the corporate’s founder.

Galvin, seeing the potential of the 6800, and anxious that it would change Motorola’s different merchandise, requested the staff:

You perceive that you just’re placing our buyer’s chip — or system — on considered one of these little boards? What’s that gonna do to my different merchandise?

The 6800 wasn’t obtainable in quantity on the time of its announcement, however samples have been quickly despatched to potential customers. By June 1974 key potential clients, corresponding to Hewlett Packard, had prototype programs constructed across the 6800.

With the launch of the 6800, Motorola did not simply have a promising product. It additionally had a proficient and modern staff in Phoenix. Together with Tom Bennett, the staff included Invoice Mensch, Invoice Lattin, Rod Orgill and Chuck Peddle, every of whom would go on to have extremely distinguished careers.

Every thing was trying good for Motorola’s nascent microprocessor enterprise. However then, in early 1974, not lengthy after the 6800 was introduced, Motorola’s administration determined to maneuver the staff to Texas.

The expansion of Motorola’s semiconductor enterprise within the early Seventies meant that the agency wanted to increase its manufacturing capabilities. Austin, Texas was chosen as a brand new web site and administration determined to maneuver the 6800 staff there.

Invoice Lattin began to journey to Austin to arrange for the transfer, while changing into more and more involved in regards to the disruption it will trigger. The semiconductor business was about to enter recession and Motorola’s semiconductor enterprise was shedding tens of millions of {dollars}. The corporate would shortly lay off hundreds of employees. Lattin later recalled that he informed Motorola’s administration:

Pay attention, you already know, circumstances are worsening within the setting right here, and that is our final time to name off this transfer. I don’t wish to get half-way right down to Austin and have this factor blow up on me.

He extracted a promise from his supervisor that engineers who made the transfer to Austin could be safe of their jobs. The transfer went forward in the course of 1975, shortly after the 6800 had entered quantity manufacturing on the finish of 1974. Then, Lattin’s boss misplaced his personal job and his substitute began to demand job cuts within the 6800 staff. It was an excessive amount of, and shortly Lattin took up the long-standing supply from his former instructor Andy Grove to hitch him at Intel.

Different key members of the 6800 staff, together with Tom Bennett, declined to maneuver to Austin, and as a substitute moved to different enterprise items inside Motorola.

And, probably most damaging of all for Motorola, the transfer to Austin had already prompted among the staff, together with Rod Orgill and Invoice Mensch, to depart and begin work on the design of a competitor. It was Chuck Peddle, who had joined the 6800 staff later in its improvement, who was the driving drive behind the transfer. Mensch has stated that when Peddle joined Motorola “… his intention was to raid Motorola for engineers.”

One can sense Peddle’s discontent at Motorola. Within the e book ‘Commodore: A Firm on the Edge’, Peddle is lower than flattering in regards to the 6800:

They type of muddled their method by means of the structure of the 6800, which had some flaws in it. … I used to be capable of repair a few of these flaws, but it surely was too late for others.

Nevertheless, when Peddle introduced the 6800 and its household to clients, the most important concern wasn’t the 6800’s structure, however its value. The 6800 processor was launched with a value of $360, carefully matching the value of the newest 8-bit Intel processor, the 8080. Peddle later recalled that in his displays: 

The fellows would sit down, we might clarify the 6800, and they’d … fall in love …

However this was adopted by complaints in regards to the value. Prospects would say:

You are charging an excessive amount of for it. What I wish to use it for is to not change a minicomputer. I wish to use it to exchange a controller, however at $300 per system it is not cost-effective.

Peddle began to push Motorola’s administration to supply a low-cost model of the 6800. For easy management purposes, the competitors was both a customized design or Intel’s 4-bit 4040 processor. The 4040 value round $29, so Peddle set a goal of $20 for a low-cost model of the 6800. After months of attempting to get Motorola’s administration to undertake his proposal, he was instructed, in writing, to cease pursuing the concept. His response was a letter to Motorola’s administration, stating that, in Peddle’s phrases:

That is product abandonment, subsequently I’m going to pursue this concept alone. You haven’t any rights to it as a result of this letter says you do not need it.

However there was a cause the 6800 was costly. It was made utilizing ‘contact lithography’, the place the photomask, containing the picture that’s to created on the silicon die, comes into direct contact with the silicon wafer. This inevitably led, over time, to break to the photomask, lowering yields and finally rendering the costly photomask unusable. Making a low-cost model of the 6800 could be unattainable with no less expensive manufacturing course of.

Peddle was decided to pursue his thought and, while nonetheless at Motorola, began to speak to a lot of different corporations about making it a actuality. In accordance with Peddle:

And the man I went to construct first was L.J. Sevin at Mostek. And L.J.’s remark to me a lot later was, “I did not do the deal as a result of I used to be afraid Motorola was going to sue you, and I did not wish to take care of Motorola”.

Finally, he made contact with John Paivinen whose firm, MOS Expertise, primarily based in Pennsylvania, was already constructing advanced calculator chips. Peddle’s imaginative and prescient appealed to Paivinen, however there was one downside. His agency was utilizing a PMOS fabrication course of and didn’t have a working NMOS course of, that may be wanted for the brand new processor. Nevertheless, Paivinen satisfied Peddle that his agency may have NMOS in manufacturing within the yr or so it will take Peddle and colleagues to design a brand new processor.

So, in August 1974, Peddle, Orgill, Mensch and 5 different members of the 6800 staff, travelled to MOS Expertise’s Valley Forge workplaces. In accordance with Peddle, “I used to be capable of scoop up the perfect individuals from the Motorola design staff.”

There they began making the concept of a low-cost 8-bit microprocessor a actuality.

The 6800 had been introduced in April 1974 however Motorola’a shift from PMOS to a brand new NMOS course of proved problematic and it wasn’t till November that it was in quantity manufacturing, giving Intel’s 8080 a transparent six-month lead.

The 6800 staff hadn’t been working to make a competitor to the minicomputer. The goal was gadgets corresponding to ‘dumb’ ‘Cathode Ray Tube’ terminals, used to hook up with ‘actual’ mini and mainframe computer systems. An early proposal for a extra superior 16-bit processor design, that may have been aggressive with minis, had rapidly been rejected as impractical.

However the availability of the Intel 8080 in 1974 had enabled the creation of the Altair 8800, the primary commercially profitable ‘private pc’. Launched in January 1975, the Altair 8800 was the machine for which Invoice Gates would write Microsoft’s first product, a BASIC language interpreter.

The later availability of the 6800 in manufacturing meant that the primary 6800-based private computer systems trailed the Altair 8800, however they nonetheless made an influence. Main the way in which was the South West Technical Merchandise SWTPC 6800, launched on the finish of 1975. The SWTPC supplied a 6800 card plugged right into a printed circuit board ‘backpane’ and related to a variety of peripheral playing cards by way of the SWTPC’s SS-50 bus. Playing cards to assist floppy disk drives, video shows and different peripherals have been quickly obtainable.

The Altair and the SWTPC machines could seem primitive now, however their low value – the SWTPC 6800 was launched with a beginning value of $450 – their relative ease of use, and the flexibleness of with the ability to add new peripherals, have been revolutionary. Motorola might have been a bit of late in delivering the 6800 however on the finish of 1975, they’d a promising foothold within the new private pc market.

In the meantime, Peddle and 7 of the Motorola engineers had travelled throughout the nation to Valley Forge in Pennsylvania, arriving at MOS Expertise’s workplaces on 19 August 1974. Their arrival wasn’t welcomed by all at their new employer and Mensch has recalled how he as soon as discovered nails within the tyres of his automotive parked outdoors the workplace, which he attributed to a resentful MOS Expertise engineer. A kind of engineers has recalled that he thought Peddle could possibly be ‘a bit pompous’ however that ‘he’d had a imaginative and prescient and was pushing that imaginative and prescient. Peddle was the visionary’.

Only a yr after they’d made the transfer to Pennsylvania, Peddle, Orgill, Mensch and their colleagues had created a number of new low-cost 8-bit processors. The important thing designs have been the MOS Expertise 6501 and 6502, with the 6503, 6504, 6505 and 6507 as cheaper variations in 28-pin (moderately than 40 pin) packages with decreased deal with areas.

To create these new microprocessors the engineers had wanted to work exceptionally lengthy hours, with cots put in in among the workplaces in order that they might take naps earlier than returning to work. The microprocessor’s circuits have been drawn on paper by hand in a repetitive and error susceptible course of. When the staff found that considered one of their designs was too large they needed to rework it, circuit by circuit, reclaiming small quantities of house on the die.

There have been competing claims about who ought to get the credit score for the structure of the 6502. It’s usually been attributed to Invoice Mensch, and Chuck Peddle has paid tribute to Mensch’s work:

“He constructed seven completely different chips with out ever having an error, virtually all achieved by hand. Once I inform folks that, they do not imagine me, but it surely’s true. This man is a singular individual. He’s the perfect structure man on the earth.”

Nevertheless one other member of the staff, Harry Bawcom, has disputed this declare

“Invoice Mensch didn’t structure the 6502, I did, with the assistance of two others.

In fact all of us labored as a staff however Invoice did not draw a single line on the primary model of the 6502. My initials have been on the die. … There have been two different circuit designers concerned, one senior to Invoice. They deserve credit score, too.”

Equally necessary, though much less nicely publicised, was the hassle of the MOS Expertise course of engineers to develop a working NMOS course of and to maneuver away from contact lithography. As Paivinen had promised, they’d a working NMOS course of prepared in time to make the brand new microprocessor designs.

One of many key options of the 6501 was that it could possibly be plugged into the identical socket on the printed circuit board because the 6800. In accordance with one colleague:

Chuck offered the idea that Motorola might be on the market constructing all these boards that may use the 6800 and we’re going to come back together with. a value decreased microprocessor to exchange it pin for pin.

And clients may instantly use the {hardware} ecosystem that Motorola had already designed for the 6800 as the place to begin for a 6501-based system, ‘leap beginning’ their 6501/2 improvement.

The 6502 would run the identical code because the 6501 however was not ‘pin-compatible’ with the 6800. Nevertheless, it was easier to combine into programs, needing solely a single clock sign, in comparison with the 2 clocks that have been wanted for each the 6501 and 6800.

If we put the dies (cube) of the 6800 and the 6502 facet by facet then the similarities between the 2 designs grow to be clear. Each designs have a ‘Programmable Logic Array’ ‘management ROM’ on the high, management logic within the center and registers and arithmetic and logic circuitry within the backside half of the die.

Beneath the floor, although, the 2 designs have been very completely different. The 6501/2 have been every smaller, needing simply 3,500 transistors, in comparison with 4,100 for the 6800.

The 6501/2 would each be fabricated utilizing an NMOS, depletion-load course of whereas the 6800 had been designed to make use of a much less superior course of. And MOS Expertise pioneered the transfer away from utilizing contact lithography, eradicating the necessity to create costly new masks frequently.

And the 6501 and 6502 wouldn’t be code-compatible with the 6800. Economies had wanted to be made within the new designs to maintain the transistor depend down. The 16-bit ‘stack pointer’ within the 6800 was decreased to 8-bits, which might all the time level into web page 1 (hexadecimal addresses 0100 to 01FF) in reminiscence. The 6800’s two 8-bit accumulators, ‘A’ and ‘B’, have been changed by a single ‘A’ accumulator. Room was discovered, although, for 2 8-bit index registers ‘X’ and ‘Y’, changing the only 16-bit index register within the 6800.

The staff discovered a lot of different methods of simplifying the designs. The primary model of the 6800 had measured 29.0 mm^2. The 6502 was solely 16.6mm^2. So virtually twice as many 6502s could possibly be extracted from a silicon wafer when in comparison with the 6800. Crucially too, the smaller die measurement and the transfer away from contact lithography meant that yields, which had been a significant downside for Motorola, could be considerably larger too. In accordance with Mensch their design “yielded 10 instances as many good chips because the competitors.” The 6502 could be a lot, less expensive to make than the 6800.

This decrease value had been achieved with out sacrificing efficiency. Let’s take a look at one key instance of how this was achieved.

The static RAM cells wanted to create registers on the CPU have been costly when it comes to die space. This meant that the groups designing each the 6800 and the 6502, have been each restricted within the variety of registers they might afford to incorporate. Because of this, each chips would want to load and retailer values from reminiscence extra usually than a competitor just like the Intel 8080, which had many extra registers. So, each the 6800 and the 6502 had two-byte directions that may retailer the worth in an accumulator to a specified location in web page zero (hexadecimal addresses 0000 to 00FF) in reminiscence. For each processors, this is able to execute in three clock cycles.

However the 6502 went a lot additional in making use of web page zero. It added directions that may add two bytes from web page zero to the Y register to type the deal with for use in a load, retailer, arithmetic or logic operations. These directions made some frequent operations corresponding to copying small quantities of reminiscence, sooner than the 6800. Let’s take a look at one instance of this in observe.

Wikipedia has an instance of code with the 6502’s new addressing modes in motion in a ‘reminiscence copy’ subroutine. Within the extract beneath the contents of SRC and DST, that are each reminiscence areas in Web page Zero, are used as ‘base addresses’ and the Y register is added in every case to create the ultimate supply and vacation spot addresses.

So, extra particularly, right here SRC is #80. The instruction:

LDA (SRC), Y

Takes the contents of #80 and #81 creates a two byte reminiscence deal with from the contents of those (web page zero) reminiscence areas, provides the Y register to this deal with to create a brand new reminiscence deal with after which masses the contents of that reminiscence deal with into the accumulator.

All this occurs, usually, in simply 5 ‘clock cycles’ an overhead of only one clock cycle when in comparison with studying the accumulator from a hard and fast two byte deal with in reminiscence. Even higher, different directions supply arithmetic and logical operations that use the identical addressing mode for no further clock cycles when in comparison with a easy ‘load’. These directions learn two bytes from reminiscence, add Y to these two bytes to type a reminiscence deal with, then learn an extra byte from reminiscence and carry out an arithmetic operation utilizing that byte. All this could occur in simply 5 clock cycles.

Some commentators have described the 6502 as a form of early 8-bit RISC ‘Decreased Instruction Set Pc’ processor. In reality, in lots of respects, the 6502 was fairly the other of a RISC design. Some frequent directions have been fairly advanced, with a number of reminiscence reads and calculations.

Quoting Invoice Mensch:

And we discovered the way to have addressable registers through the use of zero web page [the first 256 bytes in RAM]. So you may have one byte for the op code and one byte for the deal with, and [the code is compact and fast]. There are limitations, however in comparison with different processors, zero web page was an enormous deal.

In impact the 6502’s ‘web page zero’ in reminiscence offers a lot of ‘pseudo’ 8 and 16-bit registers, slower than actual registers, however nonetheless sooner and extra versatile than having to make use of different components of reminiscence. A talented programmer making efficient use of ‘web page zero’ may write code that was quick when in comparison with different 8-bit designs.

This in all probability wasn’t apparent to many early customers although, who may merely have in contrast the variety of registers with a 6800 or an Intel 8080 and located the 6502 missing. So an early MOS Expertise brochure felt the necessity to clarify the choice to cut back the variety of registers when in comparison with the 6800.

Evaluating your half to the M6800, why did you narrow the stack again to at least one web page and why did you narrow out accumulator B, and so on.?

Though the MCS6501 is a direct plug substitute for the Motorola 6800, no actual try was made to keep up precise software program compatibility with the 6800 due to our want to have considerably higher addressing flexibility and to permit for upward growth within the product household. Our major goal was to develop a low-cost processor-and all different selections have been made on that foundation.

We expect that you will discover that the usage of the second index register greater than compensates for the lack of the second accumulator and the eight-bit stack pointer helped us to cut back the price of the chip. Due to the considerably higher addressing energy, one doesn’t want to make use of the stack for apart from {hardware} and subroutine processing. Because of this, a one-page lengthy stack must be greater than satisfactory.

The identical brochure proclaimed the efficiency of the brand new designs:

What’s the efficiency of the MCS6501?

The declare that the MCS6501 beats all different aggressive eight-bit microprocessors is substantiated in two areas.

First, using the A H Programs benchmarks (the one set of benchmarks at the moment obtainable from an unbiased guide), we outperform all different normal merchandise indicated in all however one case. Second, though lately a number of of our rivals have provided premium larger frequency merchandise which will enable them to equal or outperform our processors, we might be saying higher-speed microprocessors that may keep or enhance our present efficiency edge.

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The 6501 and 6502 launched on the finish of 1975 with costs of $20 and $25, less expensive than the, by then, decreased value of $175 that Motorola was charging for the 6800.

With sooner and lower-priced designs, Peddle had what he needed to fulfil his imaginative and prescient. He would make it possible for the world knew about it.

Early ads for the 6501 and 6502 proclaimed their low value and the easy-to-follow instruction set. Peddle saved prices down by charging $10 for the 6502’s documentation, however inspired customers to make their very own copies.

Precise 6502’s have been made obtainable on the market on the WESCON pc convention in September 1975. Forbidden by the convention organisers from promoting the chips on the convention flooring, Peddle set himself up in a lodge room throughout the street. As guests crowded the MOS Expertise sales space on the present, they have been directed to the lodge in the event that they needed to purchase a CPU. A gentle stream of convention delegates crossed the street and made their strategy to the lodge room handy over their {dollars} in return for one of many new CPUs.

Within the lodge room Peddle’s spouse Shirley had a glass jar stuffed with 6502’s and would extract one to present to anybody who handed over their $25. Nevertheless, there was a component of subterfuge in the usage of the glass jars. Peddle needed to point to guests that they’d a plentiful provide of the brand new chips. However in accordance with Peddle:

Solely half of the jar labored… we knew that those on the backside of the jar did not work, but it surely did not matter. We needed to make the jar look full.

Phrase unfold rapidly past WESCON. Inside just a few days, Peddle had signed up Atari to purchase a value decreased model of the 6502, the 6507, along with RAM, ROM and I/O chips to be used in a online game console. The value? An astonishing $12 for every chipset. The console could be the groundbreaking Atari 2600, which went on to promote 30 million items.

The third version of Byte journal, dated November 1975, featured the brand new MOS Expertise CPU on its entrance cowl with the headline “A $20 Microprocessor”.

The article itself, which will need to have infuriated Motorola, was titled ‘Son of Motorola (or, the $20 CPU Chip)”. It in contrast the 6501/2 with the 6800 in some element [See the notes below for the full Byte article]:

For the aim of accessing parts of arrays, or tables of many an identical parts, the MOS Expertise chip comes out method forward. That is partly as a result of lack of sure vital directions on the Motorola 6800, corresponding to an instruction so as to add the contents of an accumulator to the index register, and even to switch the worth within the accumulators to the index register.

And the piece concluded with:

In favor of the 6500 collection are value and pace; in favor of the 6800 are availability and superb Motorola documentation.

The 6502 would quickly be obtainable in quantity and MOS Expertise’s 6502 documentation was really fairly good.

Motorola needed to reply. They decreased the value of the 6800, from $175 to $69. And, fulfilling L.J. Sevin’s prophecy, they sued MOS Expertise. Microcomputer Digest reported in December 1975 that:

Motorola is in search of an injunction in opposition to MOS Expertise to halt the manufacture, advertising and filling of orders for MCS 6500 microprocessor merchandise. The injunction motion is meant to cease MOS Expertise from additional 6500 actions till the result of a pending trial of a swimsuit filed in Federal Court docket in Philadelphia PA by Motorola. As of but, the injunction makes an attempt have been unsuccessful. Motorola, citing a number of Motorola patents that led to the event of its personal MC6800 microprocessor, alleges that seven former workers of Motorola (Charles J. Peddle, Rodney H. Orgill, William D. Mensch, Wilbur L. Mattys, Terry N. Holdt, Ernie B. Hirt, and Harry E. Bawcom) left Motorola and joined MOS Expertise in comparable posts and helped set up that agency’s line of MCS6500 microprocessors. The swimsuit seeks triple damages plus all income MOS Expertise has made on the 6500 product line. MOS Expertise has denied the allegations and acknowledged that Motorola’s claims are unfounded.

In actuality, though the MOS Expertise staff had used their expertise with the 6800 when designing the 6501/2, there was little or no know-how used within the new designs that Motorola may declare as their very own. The fabrication course of and the instruction units have been each essentially completely different. The one vital factor that they shared with the 6800 was the pin structure of the 6501.

The monetary and authorized sources obtainable to Motorola, although, dwarfed these of the a lot smaller MOS Expertise, which was working out of money. So MOS Expertise settled, dropped the 6501, paid $200,000 in damages and returned some documentation that the engineers had taken with them from Motorola. The 2 corporations additionally cross licensed patents.

There’s a distinction of opinion within the MOS Expertise staff about their authentic intentions across the 6501. Rod Orgill, who led its design, guess Mensch, who led the 6502’s design, that the 6501 would outsell the 6502. Peddle maintained that it was all the time meant to present Motorola a goal to purpose for which could possibly be given up once they sued. In any occasion, the 6501 was designed, constructed and featured in early documentation and ads, however was by no means offered to clients.

The 6502 remained on sale although. By the tip of 1975, MOS Expertise had a brand new and extra financially secure proprietor within the form of Commodore. With the lawsuit settled and MOS Expertise underneath new possession, it was quickly clear that Motorola’s administration had, with the transfer to Austin, stimulated the creation of a brand new and credible competitor.

The mixture of low value and higher efficiency was a successful system for the 6502, and it quickly discovered its method into designs which may in any other case have used the 6800. Probably the most well-known instance of this occurred in 1975 when Steve Wozniak needed to construct his personal single-board pc. Having in contrast the Intel 8080 and the 6800, he settled on the Motorola chip, preferring its extra elegant instruction set, and labored to develop his design utilizing the chip.

However even the decreased $175 value of the 6800 was greater than Wozniak may handle. When the 6502 appeared on the finish of 1975 its $25 value was, ultimately, reasonably priced so he switched to the MOS Expertise design. Wozniak teamed up with Steve Jobs, turned his single board design right into a business product, and offered it because the Apple pc. The design would retain the flexibility to make use of a 6800, although, with house allotted on the circuit board for the Motorola design for use rather than the 6502. Nevertheless, not one of the computer systems, later often called the Apple I, have been ever tailored to make use of the 6800.

When Wozniak and Jobs created the Apple II, their expertise utilizing the 6502 within the Apple I, made it sure that they’d use the MOS Expertise design.

And now that MOS Expertise was owned by Commodore, variants of the 6502 grew to become the processor in a variety of standard Commodore pc designs from the PET and VIC 20 to the Commodore 64. Possession by Commodore proved to be no barrier to adoption by Apple or different Commodore rivals and the 6502 would go on for use in private computer systems made by Atari, Acorn and plenty of others.

For extra on the 6502, then ‘65 Causes to Rejoice the 6502’ has tons extra on the historical past of the chip on the coronary heart of the Apple II, Commodore 64 and plenty of extra necessary machines.

The parallels between the tales of the 2 hottest microprocessor architectures of the 8-bit period are hanging. Intel and Motorola each produced modern designs that helped to create the early private pc market. Each corporations then drove away the groups that had created them, solely to see these groups create higher designs, at Zilog and MOS Expertise respectively, that may go on to steer the 8-bit market.

Bob Galvin, Motorola’s CEO, instantly understood the importance and the potential of the 6800. Motorola’s administration have been informed that the transfer to Austin could be extremely disruptive. But they continued with the transfer, even after they’d misplaced a number of key members of the 6800 staff.

Motorola’s mistake led to the creation, at MOS Expertise, of the microprocessor that may energy most of the hottest early residence and private computer systems, together with the Apple II, Commodore PET, Commodore 64 and BBC Micro. The 6502 was each highly effective and stylish. Quoting Invoice Mensch:

There’s a love for this little processor that is plain.

Chuck Peddle would later reminisce, fondly, about his expertise creating the 6502.

It was a singular time in historical past, you solely get to do a kind of in your lifetime, I believe.

It was a unique story for Motorola. The transfer to Texas and the creation of the 6502 had been main setbacks for the 6800. They weren’t the tip of the story for Motorola’s 8-bit efforts, although. In Half 3 of the story of the 6800, we’ll take a look at the later variants of the 6800 and the 6809, Motorola’s closing 8-bit successor to the 6800 and, arguably, probably the most highly effective 8-bit processor of the Seventies.

After the break, additional studying on the event the 6502 by members of the previous Motorola staff, with interviews, oral histories and extra.