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Feb. 2, 2004
Wireless & Visual Communication Co., Ltd.
WPAR is a reference board of wireless multimedia receiver, aiming to be an application development platform for wireless transmission of audio, image, and video contents.
It is equipped with Renesas SH7751R that works at 240MHz, which allows developers to take full advantage of fast and stable SH-Linux technologies.
A wireless network interface conformed with IEEE 802.11b is connected to WPAR via PC card slot, allowing for keeping up with the latest wireless LAN standards such as IEEE 802.11a and IEEE 802.11g by upgrading the network card.
WPAR's outstanding graphics capability is realized with two controller chips: Silicon Motion's SM501 for 2D image rendering, and VWeb's VW2010 for audio and video decoding. SM501 has several video layers including two graphics layers, two alpha layers, and a video layer, which are utilized for smooth display of image sequences with double buffering, and for building window GUIs. VW2010 supports a number of audio and video formats such as MPEG-1/2/4, their audio layers, AC3, and so forth. The decoded video is simultaneously outputted as VGA and NTSC formats. In addition, VW2010 also has multiple video layers, which enables overlaying of captions and images on moving pictures. This powerful combination of graphics chips releases the CPU from video processing loads and allow it to run interactive tasks during video playing.
Finally, all these features are implemented with selected components in terms of power consumption and thermal emission. As a result, WPAR does not require cooling fans, thus, is the best solution for embedded applications.
This device is formed by 4 functional blocks below:
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| CPU | SH7751R 240MHz | Renesas Technology |
|---|---|---|
| Main Memory | SDRAM 64MB | |
| Video RAM | 16MB (SM501), 8M(VW2010) | |
| Flash ROM | 16MB | |
| Graphic controler | SM501 | Silicon Motion, Inc. |
| Video codec | VW2010 | VWEB |
| Wirelss LAN | 802.11a/b/g | Key Stream |
| USB | x1 | USB 1.1 |
| Video out | Composite, S | NTSC |
| Audio out | RCAx2 | Stereo |
| VGA out | Standard VGA | VGA upto SXGA |
| LED | x3 | |
| Button Switch | x4 | |
| JTAG | 14 pin JTAG(H-UID) connector |
Figure 1 shows the block diagram of the reference board. The SH7751R (Renesas) is a 32 bit RISC microprocessor. It consists of the SH-4 CPU working at 240MHz, MMU, PCI bus controller, and BSC. Those built-in functions lead to lower system costs. A flash ROM for file system, SDRAM for main memory, graphic controller, and GPIO are connected to the local bus, while a video codec LSI and card bus bridge are connected to the PCI bus. Finally, it is equipped with a USB-UART bridge for a serial console. Specifications of the reference board are given in Table 1.
The SM501 (Silicon Motion Inc.) is a graphic controller chip with direct CPU bus interfaces. 16MB video RAM enables high resolutions up to 1280 x 1024, including a 1280 x 768 wide screen. It supports hardware video overlay, video scaling, and color space conversion from YUV to RGB. Table 2 gives the details of SM501's multiple video layers.
The VW2010 (Vweb Corp.) is an audio and video codec chip that supports real time decoding of MPEG-1/2/4 and H.263 video stream as well as MPEG-1/2 audio layers AAC, and AC-3 audio stream. With 8MB external SDRAM, it supports adaptive field/frame motion compensation and DCT types for high quality video decoding. It outputs ITU-R BT656 video signals through video DAC leading to S and composite video connecter as well as audio signals through audio DAC to RCA plug. The video signal is also transmitted to the graphic controller, through ZV port, and it is displayed on the SM501 video layer. The VW2010 has multiple video planes: two graphic planes that support alpha blending a hardware cursor plane. Table 3 shows the supported video formats in detail.
