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I2C
Invented by Phillips in the early 1980s, the Inter-IC (I2C) bus has become the de facto worldwide
standard for system control. It can be found in everything from temperature monitors and voltage
level translators through EEPROMs and general-purpose I/Os to data converters, CODECs and
microprocessors. A simple two-wire bus with a software-defined protocol, it is used to transfer
data between IC’s of all kinds over distances up to one hundred metres.
One of the keys to the enduring success of the I2C bus is the way its performance has kept pace
with changing market demands. Today, three data transfer modes are available: Standard (100
Kbps), Fast (400Kbps) and High-speed (3,4 Mbps). In addition, Philips’ recently introduced hubs,
repeaters, bi-directional switches and multiplexers that have extended the capacity of the I2C bus
far beyond its original 400 pFmaximum capacitive bus loading limit.
The ease of use of the I2C bus has also added to its popularity. Any I2C device can be attached
to a common I2C bus, and any master device can interact with any slave. The softwirecontrolled addressing scheme eliminates the need for address-decoding hardware, while control
logic is provided by the bus protocol. Furthermore, the latest generation of I2C devices supports
hot insertion, minimising downtime when maintaining or expanding a system.
Some I2C-based families Philips offers: ADCs; parallel bus to I2C bus controllers; I2C bus
repeaters, hubs and extenders; EEPROM based DIP switches; LED dimmers/blinkers; generalpurpose quasi and true I/O; multiplexers and switches; I2C serial EEPROM; temperature and
voltage sensors; voltage level translators.
UARTs
The Universal Asynchronous Receiver/Transmitter (UART) first appeared on the market in the
late sixties and offers data rates up to 5 Mbps with a maximum range of 500m. With its low cost,
long lifetime and ease of use, it is still widely regarded as the best way to transfer data from a
microcontroller to other parts of the system and is extensively used for this purpose.
Philips has considerable experience in UART development, and is a leading supplier of industrial
UARTs. Its extensive portfolio includes families of pin-compatible devices, offering drop-in
upgrades to higher speeds, deeper FIFOs, etc. And to meet the demand for more functionality
from smaller end products, the company has developed a new UART range specifically for
space-constrained applications. These tiny devices deliver space saving of up to 70%, typically
without requiring the redesign of the PCB.
Some UART families Philips offers: Industrial UARTs (SC28xxx); SC16CxxxB UARTTs; Impact
Range.
CAN
Originally developed for in-vehicle networking systems, the Control Area Network (CAN) bus is
also now increasingly common in industrial and medical applications. Used to link electronic
control units (ECUs) together to form networks, it offers data transfer up to 1 Mbps over distances
up to 40 m, or 5 Kbps for longer distances up to 1 km. A choice of three physical layer options is
available to meet the demands of various applications: high-speed CAN (HS-CAN) for the highest
data rates, fault-tolerant CAN (FT-CAN) for maximum reliability, and single-wire CAN (SW-CAN)
for cost-down applications.
Philips has long been a leader in CAN, and its PCA82C250 is still one of the most widely used
CAN transceivers. The company has one of the widest CAN portfolios on the market, with
extensive packaging options to fit any design. But Philips does more than just offer baseline
compliance, and is continually expanding an impressive array of added-value products and
innovations that have already become industry standards.
Some CAN families Philips offers: stand-alone CAN 2.0B controllers; 8-, 16- and 32-bit
microcontrollers with embedded CAN; automotive- and industrial-grade transceivers for HS-, FT-,
and SW-CAN.
USB
The Universal Serial Bus (USB) is the world’s most popular interface for high-speed data transfer
between PCs and peripherals such as printers and digital cameras. It offers three data rates: low
speed (up to 1.5 Mbps), full speed (up to 12 Mbps) and high speed (up to 400 Mbps). With evereasier access to services and the ability to create their own content, consumers also want to be
able to share this material between devices and with friends. USB provides a convenient and
familiar way to deliver this, and so is an attractive addition to many products.
Philips has been heavily involved in USB from the start and helped drive two recent technological
developments to expand its potential even further. With its low power consumption and small
form factor connectors, USB On-The-Go (OTG) was designed to extend the applicability of USB
2.0 in the portable domain. It enables ‘peer-to-peer’ communication by equipping peripheral
devices with limited host capabilities. This allows consumers to transfer data from, say their
camera to their mobile phone without the need for a PC host.
The UTMI+Low Pin Interface (ULPI) provides a standard 12-pin interface between a USB 2.0
transceiver and the USB logic embedded within complicated Ics. It allows designers to offer
greater USB functionality while reducing time-to-market and end-product size. Furthermore, it
ensures interoperability between transceivers.
Besides being instrumental in developing the ULPI and OTG standards, Philips was the first
company to offer semiconductor solutions that meet them. However, Philips’ USB offering is not
only about hardware. Comprehensive support tools include mature USB Software-working with
any operating system, the software offers a proven platform for rapid design-in. For example, the
software for USB 2.0 supports WinCE, Linux, Symbian, VxWorks, Uitron and Nucleus. Philips
also provides firmware and software stacks, evaluation kits and example applications, reference
designs and tutorials, etc to simplify the designer’s job.
Some USB families Philips offers: hub controllers; host controllers; peripheral controllers;
transceivers; OTG controllers; ULPI transceivers.
TYPE
I2C
UART
TYPICAL USE
Transfer serial data between
Ics of all kinds
Transfer data streams from an
MCU to other system parts
MAXIMUM DATA RATE
RANGE
100 Kbps (Standard)
400 Kbps (fast)
3.4 Mbps (high)
5 Mbps
2 m to 100 m
Up to 500 m
CAN
Link several ECUs together
Into a network (automotive &
Industrial)
5 Kbps
1 Mbps
Up to 40 m
Up to 1 km
USB
Link peripheral to host devices
(monitor to PC; camera or
Phone to printer, etc)
1.5 Mbps (low speed)
12 Mbps (full speed)
400 Mbps (high speed)
Up to 5 m