I/O and memory come together for system expansion

Philips has developed the industry's first I2C integrated devices that combine I/O expansion and nonvolatile memory functions in one.

Philips has developed the industry's first I2C integrated device that combines both I/O expansion and nonvolatile memory functions (EEPROM) on one device.

This integration offers 33% savings in board space.

The devices are simple drop in replacements that add memory space to boards without the hassle of a board redesign.

Philips' PCA9500 and PCA9501 devices are ideal for applications such as multicard systems for telecomms equipments, and maintenance in computing, communications, and consumer systems that need both general purpose inputs/outputs (GPIO) and nonvolatile memory.

"Kodak developed a film-processing machine with several distributed CPUs and needed a non-software-based mechanism to provide hard reset and handshaking for code updates.

Additionally a small amount of Flash memory was needed to store serial numbers and nonvolatile setup parameters in these CPUs.

Philips' PCA9501 chip fit our needs perfectly by providing eight I/O lines directly accessible through the I2C interface along with 256byte of EEPROM", said Doug Jensen of Kodak.

"Since our system had 31 different device addresses, the six address lines on the PCA9501 proved extremely useful, by providing the needed flexibility to place the 9501s so they would not conflict with existing hard-coded I2C addresses of other devices".

"Philips has introduced an industry first by offering integrated devices that combines both I/O expansion and memory functions that allow designers to build denser and smaller systems than was previously possible", said Pierre-Yves Lesaicherre, General Manager, Specialty Logic Product Line, Philips Semiconductors.

"Philips' expertise in I2C technology adds to our leadership in providing essential multimarket semiconductors".

Philips introduced these devices to extend the use of the I2C bus or SMBus for larger system configurations or smaller form factors, enabling manufacturers to simplify the design process.

The PCA9500 is a 16-pin device that is pin compatible with the Philips' PCF8574 and I2C address compatible with the 24C02 2Kbit EEPROM.

The three hardware address pins (A0, A1, A2) vary both the GPIO and EEPROM I2C addresses.

This allows up to eight devices to share the same I2C/SMBus bus, eliminating the need to multiplex the bus into smaller subgroups when multiple devices are needed in larger designs.

The PCA9501 offers the same key features as the PCA9500 except that it is enclosed in a 20-pin package.

This extra space allows for three additional address pins and an interrupt output pin.

The six address pins allow up to 64 devices to be physically located on the same I2C bus or SMBus.

This is particularly useful in backplane applications where 16 to 24 cards are typically connected in a multipoint arrangement to the same bus master.

This is similar to the advanced photo-processing machine that is used at Kodak.

The PCA9500 and PCA9501 will begin volume production towards the end of Q4 2002 and are available in SO and TSSOP packages.

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