If you mean by "8051-based" all micrcontrollers inspired by the 8051 instruction set and/or code-compatible with the original 8051 Intel device, then yes, perhaps the number is much higher than 7 billion. That said, I do not think this will last for long as 32-bit microcontrollers on modern process technologies are fast, energy-efficient, feature-rich and as cost-effective as 8-bit microcontrollers. 8051 is mainly legacy hardware IMO.
That is cumulative sales to date, Luis, and that seems about right to me. PIC has been the most popular microcontroller out there for the past 2-3 decades but as you pointed out the tide is turning and Microchip is not coping well with the large and increasingly growing ARM ecosystem of microcontrollers. With the Internet of Things, I bet ARM-based micrcontrollers will dwarf the 7 billion figure within the next decade.
Cumulative ARM sales are at least 80 Billion, and with 10 Billion ARM chips sold per year well on the way to reach 100 Billion around 2015. A large proportion are MCUs (ARM7, 9 Cortex-M0 and M3), so ARM has already surpassed that 7 Billion cumulative number for 8051.
It is misleading to give a single number for all ARM cores. Just as it would be misleading to give a single number for all Motorola/Frescale cores including 6809, 6811, 68000, 68010, 68020, 68030, 68040, 68HC12, S12, S12X, S08, Coldfire varieties, PowerPC varieties, etc. Each ARM core should be scored seperately.
@Max, Regardging your comment, "Cypress Semiconductor has shipped over 1.7 billion units of its PSoC 1 Programmable System-on-Chip... Good grief -- 1.7+ billion units -- I would never have guessed!"
I understand your surprise. It's been a quiet revolution for Cypress in the MCU space, but keep in mind that PSoC1 is the original platform from which CY launched their touch screen controllers and capacitive sense controllers that find their way into all sorts of consumer electronics, control panels, and white goods.
@elctrnx_lyf: All we could see might be the ARM based micro controllers and ARM based processors in the future.
ARM are ceruainly doing very well, but there are a number of other interesting players out there, like CEVA for DSP cores and Tensilica (now part of Cadence) for customizable data-plane processor cores -- plus there are wildecard processors like the Epiphany from Parallella.
I love ARM ... but were they dominant 20 years ago? Will they still be dominant 20 years into the future? (Ask me in 20 years and I'll give you the answer :-)
Yes that's true and this will still continue the usage of the evergreen 8-bit CPU based on 8051. Even PIC is simply an other variant of 8051 one can say, as the concept in design is same only RISC and CISC is the difference. Hats-off to 8051/8Bit Arch.
It was back in 1995 when my Motorola Rep called me to announce that MC68HC05 Sales had hit the 3 Billion mark at the end of '94. That was 18 years ago. What that chip couldn't do was ably augmented with the MC6808. Prettiest 8 Popper at the dance.