Apple II Slot system

Apple II Slot System is the powerful and flexible system which every Apple II and Apple ][+ has.

Apple II has eight almost identical 50-pin expansion slots, named from SLOT0 up to SLOT7. They are almost identical because SLOT0 and SLOT7 are a little different from others.

SLOT0 is special because It DOES NOT HAVE the 256 bytes spaces (/IOSEL) as all others slots have. It is used typically for the firmware card or the 16 KB Apple II Language Card.

SLOT7 is special because it has the same signals all other slots have plus two exclusive signals. It is used for Video related boards, like PAL Encoder Card in Apple II EuroPlus. These two additional signals are: (1) on pin 35 a signal of 3.5Mhz COLOR REFerence from video generator; (2) on pin 19 the SYNC signal from video generator.

All I/O is memory mapped (6502 does not have exclusive I/O oriented instructions like z80 has). In Apple II architecture, a window of 4KB is reserved for I/O with addresses between $C000 and $CFFF, this memory range is called I/O space.

The 4KB I/O space is divided in two halves of 2KB each: (1) space for 8 slots I/O, addresses from $C000 to $C7FF; (2) common area for all slots, addresses from $C800 to $CFFF. In this first half, each slot has 16 bytes for register use plus 256 bytes for address use, in this space there is also the soft switches; The second half is shared among all slots, used when card’s firmware is big and the 256 bytes from slot exclusively are insufficient.

(128 bytes)
$C000..$C07F = Soft switches 

(16 bytes each region)
$C080..$C08F = Slot 0 /DEVSEL
$C090..$C09F = Slot 1 /DEVSEL
$C0A0..$C0AF = Slot 2 /DEVSEL
$C0B0..$C0BF = Slot 3 /DEVSEL
$C0C0..$C0CF = Slot 4 /DEVSEL
$C0D0..$C0DF = Slot 5 /DEVSEL
$C0E0..$C0EF = Slot 6 /DEVSEL
$C0F0..$C0FF = Slot 7 /DEVSEL

(256 bytes each region)
$C100..$C1FF = Slot 1 /IOSEL
$C200..$C2FF = Slot 2 /IOSEL
$C300..$C3FF = Slot 3 /IOSEL
$C400..$C4FF = Slot 4 /IOSEL
$C500..$C5FF = Slot 5 /IOSEL
$C600..$C6FF = Slot 6 /IOSEL
$C700..$C7FF = Slot 7 /IOSEL

(2048 bytes)
$C800..$CFFF = Common area (2KB ROM)

The common area for all slots has 2KB, in address range from $C800 to $CFFF. This area is shared among all slots. Whenever some slot wants to use data from its ROM mapped into this area is must access (read or write?) address $CFFF to deselect all eventually ROM that could be mapped into this area; after this the correct ROM should be selected. In summary, the protocol is simple: wherever somebody access address $CFFF, all cards that has a ROM mapped in common area must deselect it (inhibit its output).

MSX ROM Cartridge

How to wire a simple ROM cartridge to connect to your MSX Computer

How to wire a simple ROM cartridge to connect to your MSX Computer.

From MSX BUS, each physical slot has a signal called /SLTSL, activate in low, which signals when CPU may want access physically that slot. Note that this signal do not specify if it is a memory read, memory write or even a memory refresh cycle (?).

Another interesting signals are: /CS1, /CS2, /CS12, activate in low, which signals when CPU want to read that memory address range. In this case, It’s for sure a memory read! BUT every slot will receive this signal, so you can not tell if this read attempt is for you or not.

Signal /CS1 activates when memory read address is between &H4000 and &H7FFF; signal /CS2 activates when memory read address is between &H8000 and &HBFFF; and /CS12 when address is between &H4000 and &HBFFF.

So to connect a simple ROM you’ll use two signals: /SLTSL to chip enable and /CS1 or /CS2 or /CS12 to output enable.

IMPORTANT: DO NOT use /SLTSL to output enable because it can be asserted in a memory write cycle, which will lead to a bus contention.

Summary

16KB cartridge (PAGE1, addresses &H4000..&H7FFF)

  • MSX /CS1 -> ROM /OE
  • MSX /SLTSL -> ROM /CE
  • MSX A15 -> ROM A14
    • or: GND -> ROM A14
  • MSX GND -> ROM A15

16KB cartridge (PAGE2, addresses &H8000..&HBFFF)

  • MSX /CS2 -> ROM /OE
  • MSX /SLTSL -> ROM /CE
  • MSX A14 -> ROM A14
    • or: GND -> ROM A14
  • MSX GND -> ROM A15

32KB cartridge (PAGES 1 and 2, addresses &H4000..&HBFFF)

  • MSX /CS12 -> ROM /OE
  • MSX /SLTSL -> ROM /CE
  • MSX A15 -> ROM A14
  • MSX GND -> ROM A15

64KB cartridge (all pages maybe not useful but it’s possible)

  • MSX /RD -> ROM /OE
  • MSX /SLTSL -> ROM /CE
  • MSX A14 -> ROM A14
  • MSX A15 -> ROM A15

REF: https://retrocomputing.stackexchange.com/questions/12701/what-is-the-circuit-for-a-16k-or-32k-msx-computer-cartridge

Zx Spectrum Next: Memory

In Zx Spectrum Next there is a lot of RAM. The RAM is divided into 16Kb banks with 256K reserved for ROMs and DivMMC interface, so in practice we have 48 banks in Next 1MB version or 112 banks in Next 2MB version mapped as follow:

Bank #Description
0..7same as standard Spectrum 128K
8..47available on all Next
48..111available only on Next 2MB version

NextZXOS uses the first 9 banks. Banks starting at 9 are always available to the programmer

Bank #Description
0standard Spectrum 48K (addr. 49152..65535)
1RAMdisk
2standard Spectrum 48K (addr. 32768..49151)
3RAMdisk
4RAMdisk
5standard Spectrum 48K (addr. 16384..32767)
6RAMdisk
7Workspace and data structures
8additional screen data on some video modes
Source: https://gitlab.com/thesmog358/tbblue/-/blob/master/docs/nextzxos/NextBASIC_New_Commands_and_Features.pdf

Some new Basic commands

  • BANK NEW var
  • BANK n CLEAR
  • BANK n ERASE
  • BANK n ERASE value
  • BANK n ERASE offset,len
  • BANK n ERASE offset,len,value
    • Fill len byte in bank n with value starting at offset

MSX Nishi book 2020

Original article: https://diamond.jp/articles/-/253320 / Translated by www.DeepL.com

The essence of failure finally revealed by the man behind the legendary PC MSX

Kazuhiko Nishi: Director, IoT Media Laboratory, Graduate School of Engineering, The University of Tokyo Management and Strategy Reflections

Kazuhiko Nishi, a “legendary entrepreneur” who was active not only in Japan but also on the world stage in the early days of IT, has published his first book, “Reflections” (Diamond Inc.). As Vice President of Microsoft, he built the foundation of an “empire” together with Bill Gates and took ASCII, the company he founded, public at the youngest age ever. However, he was kicked out of both Microsoft and ASCII and lost everything. …… is a book written by a “living legend” who experienced dramatic successes and setbacks in his twenties and thirties, revealing the other side of his life and earnestly writing about “what went wrong. In this section, we will discuss the legendary PC unification. Here, he reveals the essence of the failure of the legendary MSX, the unified standard for personal computers.

To create a unified standard for personal computers.

It was in 1983 that ASCII launched the “MSX” brand based on this idea.

Today, we can share data with any computer from any manufacturer without any difficulty, but at that time, this was not possible. Many manufacturers made their own hardware, and ASCII Microsoft, of which I was the president, customized and “ported” Microsoft BASIC to meet the specifications of each manufacturer. As a result, there was no compatibility between manufacturers or models.

If we didn’t change this situation, which was extremely inconvenient for users, we would never see the spread of the “one computer per family” concept. With this in mind, I worked with Bill Gates to create a unified standard for personal computers, the MSX, and called on Japanese manufacturers to participate. (See Part 18 of this series for more details about this process.

Just before the joint press conference was to be held on June 16, 1983, Masayoshi Son announced that he and more than a dozen other manufacturers were ready to come up with a unified standard to compete with the MSX. Just before the meeting, Masayoshi Son announced that he and more than a dozen manufacturers were preparing to come up with a unified standard to compete with the MSX. “If ASCII insists on going ahead with the MSX, Softbank Japan will advocate another unified standard and fight for leadership,” he said, issuing a “letter of challenge” to me. However, the matter was settled through the mediation of Mr. Kazuyasu Maeda of Matsushita Electric Industrial (see Part 19 of this series for details). Finally, from around October, MSX machines from various companies began to be shipped.

The price was usually around 50,000 yen. Since it was an easy-to-use computer, it became a bit of a boom during the year-end sales season. New companies started to participate in the MSX project one after another. At first, I thought it would do well.

However, Casio released an MSX machine for 29,800 yen, almost half the price. This triggered a fierce price war within the MSX camp. This was painful. No matter how hard we worked to make and sell the machine, if we could not make a profit, the project would not continue. I thought, “Oh, no”.

Even so, I think the MSX sold about 3 million units in Japan and 1 million units overseas, and it won the Nikkei Superior Products Award in 1983.

However, in later years, I was often told that the MSX was a failure. It was frustrating. It may have been only for a while, but MSX was indeed a huge craze. I wanted to emphasize that we were the ones who created it. But to those who said it was a failure, I had to say, “Yes, that’s right”. To those who said it was a success, I had to say, “Thank you very much. That was all I could do”.

Two reasons why I failed.

I feel like the media got to us.

We were making a home computer, not a game console. However, the mass media kept comparing the MSX to Nintendo’s NES and labeling it as a “failed game machine”. This was disheartening. Sure, there may have been many people who used the MSX as a game console, but that didn’t mean that it was wrong to give the impression that the MSX was a game console, and it was also annoying for business.

Because Nintendo’s NES was 14,800 yen, so if you compare it as a game machine, the other side has the advantage no matter what. But maybe Nintendo’s media strategy was a cut above ……. I’m not sure about that.

Anyway, in the end, the MSX was not able to unify the standard of personal computers, nor was it able to become a “one in the family” personal computer, so we can only say that it “failed” to achieve its original purpose.

Why did it fail? I think there are two reasons. First, I think there was a problem with the positioning.

IBM was the de facto standard for the higher-end 16-bit machines, and Nintendo’s NES was the popular version. IBM was faster and cheaper. In the meantime, the MSX was unable to fully demonstrate its significance.

The other reason, however, was the essential problem. It was that a computer, as a computer, could not become a necessary machine for a family. I had thought that if we could make a cheap and easy to use computer, computers would enter each family one by one, but that was not the case.

Having made mistakes, I was able to see the “essence”.

There was one time that made me keenly aware of this.

When I was visiting my great aunt in the hospital, I asked her if she wanted to have the MSX, the computer I built. I asked her. My great aunt replied, “No.” “It can do word processing,” she said.

I said, “You can do word processing,” and she said, “No, I have a pen.
When I said, “I can do math,” she said, “I have a calculator.
When I say, “I have e-mail,” they say, “I have a telephone.
When I said, “You can play games,” they said, “You can play TV.

There was nothing I could do. I wondered why the MSX, which I had put all my energy into developing, could not compete with ballpoint pens, calculators, telephones, and televisions. I thought about it in dismay.

Then I had an epiphany.

I had thought that if I could make a cheap, easy-to-use computer, it would become a household item, but I was wrong. But I was wrong. No matter how cheap it is, no matter how many functions it has, it will not be enough to make it popular. No matter how cheap it is, no matter how many functions it has, it will not be enough to make it popular, because even without a computer, other things will do the job. In fact, Nintendo’s NES (Nintendo Entertainment System) was a big hit at 14,800 yen, but even so, it was far from being a household appliance like a television or a telephone.

So what was missing?

After thinking about it for a long time, I finally realized. It was the lack of a network.

Telephones and televisions are connected to the network, which is why they are so prevalent, one per family. The same goes for cars.

Everyone buys a car because they are connected by a network of roads. If there were no road network, no one would buy a Lamborghini even if it sold for 100,000 yen. Without a road network, any luxury car is just a “box”.

It is the same with computers. Without a network, a computer is just a box. It is only when it is connected to the network that it becomes a necessity for every family. In the first issue of “ASCII Monthly,” I wrote, “Computers are media that can be interacted with. That’s not wrong. However, I thought that the cause and effect relationship might have been the opposite.

It is only when computers are networked and become a media that can be interacted with that they will really become popular. In other words, a computer can only become a “personal computer” when it is networked.

I learned this “essence” through the failure of the MSX. I learned this lesson through the failure of the MSX, and it led to my later PC communication business, ASCII Net.

There is one more thing I would like to say in honor of the MSX.

This was more than 10 years after the MSX. I’ve met many young and talented programmers from all over the world, and many of them have told me this story.

The first computer I ever encountered was the MSX, which my father bought for me. If it hadn’t been for that encounter, I wouldn’t be in the computer business.

I was happy. The “feelings” that we had put into the MSX to the best of our ability had certainly been conveyed to the users. And I believe that the MSX is still alive in the memories of those who used it.

Kazuhiko Nishi

Founder, ASCII Corporation. Director, IOT Media Laboratory, Graduate School of Engineering, The University of Tokyo

Born in Kobe, Japan in 1956. Dropped out of the Faculty of Science and Engineering at Waseda University. While a student at Waseda University, he founded ASCII Publishing in 1977. After hitting it off with Bill Gates, he joined Microsoft in its early days and played an active role in PC development as a board member and vice president of technology. However, he was at odds with Bill Gates over the pros and cons of semiconductor development, and left Microsoft. He returned to Japan and became a full-time “window-shopping” vice president of ASCII. In 1987, he became president of ASCII and became the youngest person ever to take the company public. In 1987, he became the president of ASCII and became the youngest person in history to take the company public, but faced financial difficulties. In 2002, after the death of Mr. Okawa, he stepped down from all CSK/SEGA positions. Since then, he has served as a visiting professor at the Media Lab of the Massachusetts Institute of Technology in the U.S., deputy director of the United Nations University Institute of Advanced Studies, professor at the Faculty of Arts and Information, Shobi Gakuen University, and is currently the president of Suma Gakuen School and director of the IOT Media Laboratory, Graduate School of Engineering, the University of Tokyo. D. in Informatics from Kogakuin University, Japan

A message from the editorial department of Diamond Inc.

Mr. Kazuhiko Nishi -.

Has there ever been a “manager” who has experienced such dramatic successes and setbacks? Kazuhiko Nishi, who was in his 20s, built the “foundation” of the Microsoft empire with Bill Gates and became the youngest person ever to take ASCII public.

However, he later experienced a number of setbacks, such as being kicked out of Microsoft after a huge fight with Bill Gates, financial difficulties, parting ways with the founding members of the company, rebellion among key executives, and falling from the position of president of ASCII.

In “Reflections,” Mr. Nishi finally reveals the factors behind his “successes and failures,” while describing the behind-the-scenes of his real-life business with such superstars as Bill Gates, Steve Jobs, Sohei Nakayama, Isao Okawa, Kazuo Inamori, and Masayoshi Son. Never before has a manager written such naked and sincere reflections.

This book is not only an industrial history of the dawn of IT itself, but also suggests the essence of business activities that will never change, and will surely provide a lot of wisdom to business people living today. We hope you will enjoy reading it.

Translated with www.DeepL.com/Translator (free version)

Translated with www.DeepL.com/Translator (free version)


BOOK: Reflections What I Learned in Business “Hell” as I Achieved Success with Bill Gates (反省記―― ビル・ゲイツとともに成功をつかんだ僕が、ビジネスの“地獄”で学んだこと)

He was the youngest person at the time to go public with ASCII, the company he founded, and made great strides in the early days of Microsoft under Bill Gates. However, he was kicked out of both Microsoft and ASCII, and lost everything. …… The “genius” who licked glory and pain finally reveals everything behind the scenes.

As vice president of Microsoft, he built the foundation of an “empire” and became the youngest person ever to take his company, ASCII, public. However, he was kicked out of both Microsoft and ASCII and lost everything…. While revealing the other side of the story, I thought seriously about what went wrong. This is the secret of success and failure revealed by the “legendary entrepreneur” recognized by Bill Gates.

Translated with www.DeepL.com/Translator (free version)

Book (Amazon.jp)

Floppy MFM: Raw Research