The SH-Mobile L3V2 processor provides features optimized for high-end phones, while the SH-Mobile UL device delivers the small size and cost-performance needed for mainstream phone models

Mobile phones that support the reception of one-segment terrestrial digital TV broadcasts are enjoying a rapid rise in popularity, to the point where phone makers are finding it difficult to differentiate their models simply by incorporating a standard reception function. This has led to requirements for advanced semiconductor devices that can enable new phone models to achieve the superior image quality needed to better display the video images.

Devices for doing this must accommodate the reality that displaying video on a small mobile phone screen requires a different sort of image processing than that required for large upright TV sets. For example, rather than faithfully rendering the natural image, the processor that drives a mobile phone screen has to provide crisp contrast and make color adjustments that depend on the scene being viewed. Also, because LCD panels are moving toward higher VGA and WVGA resolutions, the device has to provide a function that can enlarge the image to fit the screen.

Taking a lead in satisfying the requirements for higher image quality in mobile phones, Renesas has added the SH-Mobile L3V2 and SH-Mobile UL models to our very successful SH-Mobile series of application processors. The SH-Mobile L3V2 processor for high-end phones offers enhanced image quality and lower power consumption, whereas the SH-Mobile UL chip for mass-market phones offers excellent cost-performance in a small package.

The SH-Mobile L3V2 application processor uses the SH4AL-DSP CPU core and delivers 479MIPS performance at a maximum operating frequency of 266MHz (see Figure 1). Key features that enhance the image quality produced by the new device include an internal VPU5F unit, gamma- correction functions, and an enlarged-edge-enhancement function. The VPU5F is the latest version of the high-performance VPU (video processing unit) video IP that is one of the strengths of the SH-Mobile product line.

Three different gamma-correction functions are provided: histogram-expansion gamma correction, equalization correction for screen brightness (see Figure 2), and adaptive chroma correction. These functions take into account the brightness, chrominance and other properties of the input image and make the adjustments necessary for better viewing on a phone's screen. For example, the adjustments performed by the VPU5F's enlarged-edge-enhancement function include improving the look of edge regions and using dot interpolation and filtering to suppress noise. These operations prevent blurring when the image is enlarged to fit the screen.

The integration of a 24-bit audio DSP allows processing-intensive codecs such as AAC and MP3 to be used without placing an additional load on the system's SuperH CPU core. In fact, the processing load for the aacPlus standard has been reduced by over 50 percent, to less than 25MHz, by shifting some functions to hardware. The result is a longer operating time for the TV function.

The VPU5F video IP supports encoding and decoding of H.264 and MPEG-4 signals and decoding of VC-1 signals. The encoding and decoding performance for MPEG-4 is 30fps at VGA resolution. This enables the implementation of all sorts of other imaging applications besides one- segment broadcast TV reception.

The CPU and video processing IP in the SH-Mobile UL device are similar to the ones in the SH-Mobile L3V2 chip. However, the other functions it provides have been optimized specifically for terrestrial digital TV broadcast reception in pursuit of small size and cost- performance. Incorporation of the VPU5F means the chip supports other broadcast formats, too, such as DVB-H in Europe and DMB in South Korea. That makes this lower-cost application processor ideal for mass-market mobile phones that support terrestrial digital broadcasting (see Figure 3).

To keep device size down, the SH-Mobile UL processor has fewer interfaces and pins. This has resulted in a small 224-pin, 8mm x 8mm BGA package with a mounting footprint that is approximately 30 percent smaller than the footprint of the previous model.

With the SH-Mobile series, Renesas plans to continue to take a lead in satisfying the requirements of the multimedia application market and making new models available at an early date.

For more information on the SH-Mobile L3V2 application processor, click here.

For more information on the SH-Mobile UL application processor, click here.