I2C

7.1.2Digital-to-Analog Converter (DAC)

Figure 7-1shows the schematic for connecting the I2C interface to a Linear Technology micropower DAC. The DAC output is connected to the buck converter feedback path and is controlled by the I2C bus interface unit. The DAC can modify the voltage of the feedback path, which effects the processor core voltage.

Figure 7-1. Linear Technology DAC with I2C Interface

DC3P3V

R165 1.00M

U30

SA_I2C_SDA

SA_I2C_SCL

4

1

5

LTC1663

VCC

VOUT

SDA

SCL

GND

LTEP

LTC1663C35

3

2

A8752-01

The signals SA_I2C_SDA and SA_I2C_SCL correspond to the applications processor signals SDA and SCL, respectively.

7.1.3Other Uses of I2C

Figure 7-2shows the I2C signals passing through an analog switch to a compact flash socket. Since the CF socket has all of the signals to support two CF cards, and this design only uses one CF card, the signals meant for a second card are being used for alternate functions. If you decide not to use a CF card, a different application using a CF card socket could be designed to utilize the I2C bus interface unit. If this alternate function is used, the I2C bus can be enabled to the CF socket by asserting the signal SA_I2C_ENAB shown in the diagram. If the user decides to use a CF Card, negate the SA_I2C_ENAB signal so the I2C bus traffic does not interfere with the CF card.

Note: The CF card socket is disabled if a device is inserted in the expansion bus.

7-2

PXA250 and PXA210 Applications Processors Design Guide

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Intel PXA250 and PXA210 manual Digital-to-Analog Converter DAC, Other Uses of I2C

PXA250 and PXA210 specifications

The Intel PXA250 and PXA210 processors, part of the Intel XScale architecture, were introduced in the early 2000s, targeting mobile and embedded applications. They are known for their low power consumption, high performance, and advanced multimedia capabilities, making them suitable for a wide range of devices, including PDAs, smartphones, and other portable computing devices.

The PXA250, which operates at clock speeds ranging from 400 MHz to 624 MHz, features a superscalar architecture that allows it to issue multiple instructions per clock cycle. This enhances the overall performance for demanding applications while maintaining low power usage. It supports a variety of peripheral interfaces, including USB, Ethernet, and various memory types, which contributes to its versatility in different product designs.

One of the key technologies in the PXA250 is the integrated Intel Smart Repeat Technology, which optimizes data processing, thereby reducing the amount of power consumed during operation. This feature is particularly important for battery-powered devices, as it extends the overall battery life, allowing for longer usage times in mobile environments. Additionally, the PXA250 includes a dedicated graphics acceleration unit, which enables enhanced graphics and multimedia performance suited to modern applications at the time.

In contrast, the PXA210 is a more entry-level processor, aimed at cost-sensitive applications. Operating at lower clock speeds, typically around 200 MHz to 400 MHz, it forgoes some of the advanced performance features of the PXA250 while still offering a good balance of performance and power efficiency. The PXA210 is less complex, making it suitable for simpler devices that do not require the extensive capabilities of the PXA250.

Both processors utilize the Intel XScale architecture, which is based on the ARM instruction set. They are built on a 0.13-micron process technology, enabling higher density and lower power consumption compared to their predecessors. With integrated memory controllers and bus interfaces, they facilitate efficient data handling and connectivity options.

In summary, both the Intel PXA250 and PXA210 processors played a crucial role in the evolution of mobile computing by providing powerful processing capabilities with energy efficiency. Their features and technologies enabled device manufacturers to create innovative products that catered to the growing demand for portable devices during that era.