Cypress 8-bit MCUs sport configurable peripherals

Cypress 8-bit MCUs sport configurable peripherals
By Anthony Cataldo, EE Times
July 9, 2001 (9:50 a.m. EST)
URL: http://www.eetimes.com/story/OEG20010709S0017

SAN MATEO, Calif. — Cypress Microsystems Inc. is trying to make its mark in general-purpose 8-bit microcontrollers with a flash-memory-based family that lets users configure their own digital and analog peripherals, interconnect and pinout.

The 8C25X controllers are based on the premise that most MCUs — some 10,000 of them — differ not by the type of peripherals they use but by how they are mixed. Moreover, many of these peripherals, such as UARTs, counters and timers, are so alike that a change in the register set could prompt them to change personalities on the fly.

"If you go through the thousands of part numbers and go through the different peripherals, it's a short list," said Michael Polen, vice president of marketing for Cypress Microsystems, a subsidiary of Cypress Semiconductor Corp. "The pain is all in the permutations."

Cypress' move into general-purpose 8-bit MCUs comes several years after it developed its own USB controller chips, which were based on a stripped-down 8051. For its latest 8C25X family, Cypress beefed up its proprietary MCU core and devised a way to take advantage of the similarities in the peripherals.

"All the [digital peripherals] are three register functions, and the timers, counters and serial ports are handing data back and forth in movement or comparison between those three registers," Polen said. Cypress found that with a little "over design," these peripherals could be fashioned into generic blocks made to handle the I/O functions of different peripherals, he said.

Under the scheme, Cypress has devised eight configurable generic digital blocks, four of them for higher-gate-count serial functions. Peripherals that can be created include pseudorandom sequence generators, pulse-width modulators and serial transmitters and receivers.

What's more, the peripherals can change on the fly, which could be useful in applications such as a two-way radio.

"Power it up and it's receiving. Press the talk button and it reconfigures the filter values, the inflow becomes the outflow and it becomes a transmitter. Take your finger off the button, and it goes back to being a receiver," Polen said.

As for analog circuitry, there are four resistor-based analog user modules and eight capacitor-based blocks that allow users to create gain stage amplifiers, comparators, filters, A/Ds, D/As, modulators and demodulators. A user, for example, can devise inexpensive switch capacitor filters, where capacitors surrounding an op amp are made to emulate resistors. Many of those analog functions would otherwise have to be done off-chip, Polen said.

To be sure, Cypress is a neophyte general-purpose MCU provider with a proprietary architecture competing with entrenched IC makers in the mature 8-bit MCU arena. It can hardly hope to compete against a hefty lineup of 8-bit MCUs from heavyweights like Motorola Inc. and Microchip Technology Inc. based on its line card alone.

But if Cypress can persuade some customers to change their thinking on MCUs, Polen said, it shouldn't have to worry about its thin line card, which today consists of 15 devices with 4 to 16 kbytes of flash.

So far, Polen said, no customer has committed to using the Cypress devices, which were scheduled to sample mid-month. But Polen said he's been pleased by feedback from 300 prospective customers and has delivered 1,350 design kits since February.

As further enticement, Cypress is pricing the part at $2.55 to $5.30 in 100-unit quantities, competitive with comparable MCUs in the market, he said, and is bundling its peripheral-generating "device editor" software as part of its basic free software tool kit. An in-circuit emulator and C compiler cost $150 and $145, respectively.