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The ATARI 2600 is an 8-bit Game Console


In this episode of Quick Blits we explore a topic that occasionally comes up in conversations. How many ‘bits’ is the Atari 2600? What does that mean, and makes it that way? We’ll cover the Atari 2600, Nintendo NES and SNES, Sega Masters System and Genesis… with a surprise inside!

June 13, 2022

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Yes, The ATARI 2600 IS an 8-Bit Game Console… same as Nintendo.

When the ATARI VCS was released in September of 1977, later to be rebranded as the ATARI 2600, general understanding of computers and their underlying architecture was not as widespread or accessible as it is today. At the time, no consummer would have called the ATARI an 8-bit console, because they didn’t know what 8-bit was, and at the time there was no reason why they should.

In the same year, both the Commodore PET and the Apple II were introduced, but their marketing mainly focused on things you can do with the computer and not specifically what the computer, is.

Around 1981, 16-bit computers started coming to market along with the Intel 8088 processor, followed by the 80286 in 1983. By 1984 many companies were building computers for business use. However, since the people using the computers in the office were more concerned with productivity and new business software, they rarely had any reason to know what CPU was under the hood.

Around the same time, more households started getting computers of their own, with Apple releasing the Macintosh, and companies like Compaq producing lower-cost computers. Both targeting the consumer market, and more often than not, promoting the brand over the computer architecture.

Meanwhile, in the console space, Nintendo and Sega released the NES and the Master System to the North American general public in 1986. Both systems sporting fairly comparable hardware, so the comparison was mainly with the quality of the games for each system, and not the hardware itself.

It wasn’t until the end of the 3rd generation of video game consoles when marketing for the upcoming Super Nintendo and the Sega Genesis consoles started using the term 16-bit. They did this to make a clear distinction between the 3rd generation and the new, better, 4th generation. 16-bits is better than 8-bits.

It was this huge flood in marketing that lead to the term ‘8-bit’ to be almost synonymous with the previous generation of consoles, and in particular, the Nintendo NES, which was the market leader at that time. However, the ATARI, released 9 years prior to the NES was also an 8-bit console… and both used the same CPUs.

M.O.S Technology, Inc was started in 1969 by Allen-Bradley, a factory automation company, as a small chip fabricator mainly focused on producing chips for Texas Instruments calculators.

In 1975 several chip designers joined MOS Technology after leaving Motorola where they had worked on the Motorola 6800. At the time, the designers were working on a lower-cost version of the chip when management told them to stop. Motorola has no interest in selling the chip for $25 when the 6800 was already selling well for $300. The design team was not impressed with the management’s decision and decided to leave Motorola to follow their vision.

Within the year, the team had developed the MOS 6502.

The Nintendo NES used the MOS 6502 which featured an 8-bit accumulator register, two 8-bit index registers, 7 processor status flag bits, an 8-bit stack pointer, and a 16-bit program counter.

A processor is considered an 8-bit processor when it’s data bus is only 8-bits wide.

This is what defines the NES as an 8-bit console.

The ATARI used a MOS 6507 which is a cost reduced version of the 6502. The differences being a reduction in the number of pins from 40 to 28 resulting in a loss of some interrupt lines, and reducing the address bus from 16 bits to 13 which limited the available memory range 64kb down to 8 kb. The data bus however, remains 8-bit.

When we compare the NES and the ATARI together, it’s hard to believe that the two are using essentially the same processor. The NES arguably has better color, resolution, animation, sound, bigger sprites… more sprites, smoother, faster motion.

So what’s going on here?

For that answer, we’re going to have to look under the hood of each console to see what makes up it’s processing stack

The Atari uses the 6507 with a clock speed of 1.19 MHz and 128 bytes of RAM The sound and graphics are supplied by the TIA chip which contains no on board RAM, eliminating the possibility of a frame buffer. It has 2 sprites 1x8 pixels each, and 3 other sprites that are a single pixel each. Sound is generated using two channels.

The NES, however, uses a Ricoh 2A03 which has a 6502 core running at a clock speed of 1.79 Mhz.

Graphics are handled by a separate processor, the PPU, containing 2 KB of on board RAM and a maximum of 64 sprites on the screen at one time, at 8x8 pixels per sprite.

A sound generator is integrated into the Ricoh 2A03 provides up to 5 audio channels.

So, it’s not really the processor under the hood that makes one system better than the other. It’s the combinations of technologies used to build the stack that makes up the capabilities of the console. The NES runs at much faster clock speeds, and has a frame buffer which reduces the amount of work the processor needs to draw the screen. It has much more RAM, and supports many more hardware sprites. It’s a far more capable console.

So why is it so hard to believe that the NES and the ATARI are both 8-bit consoles?

That brings us back to the marketing frenzy of 1988

In 1988, sega marketed the genesis as an 16-bit console, followed by nintendo with the SNES in 1990. This brought in the idea of the sega master system, and the NES being 8-bit into the collective consciousness.

However, no one was marketing against ATARI at this time.

With the video game crash in 1983, Atari had sustained a major blow. Many third-party studios closed, and other major publishers such as Mattel and Coleco left the video game market entirely.

There was no need to pit the master system and the NES against the ATARI 2600 because the development of the 2600 had dried up, and Atari was now focusing on personal computers.

While the 2600 did make a return in 1987, it was marketed as a budget console in order to lure in parents reluctant to pay more for the newer generation of consoles.

It’s understandable how some people may remember the ATARI 2600 as a 4 bit, or even a 2 bit console when you consider how much more you were getting with an NES compared to a 2600, but in reality, the size of the data bus determines if a processor is 4, 8, 16, 32, 64, 128-bits or more, and this has nothing to do with the graphic capabilities of the console.

Case in point, the Turbografx-16… is an 8-bit console… with a MOS 6502 at its core.

If you’re new to the channel then please consider subscribing for more videos like this, along with 8-bit history and tutorials on programming games for the Atari 2600. If you like what you see please like the video and share with your peers. If you’d like to help support the development of the channel, please consider joining me on patreon where you can make small donations that really make a huge difference.

As Always, thanks for watching, and I’ll catch you later!

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