Dedicated Engine for Advanced Cellular Phones
ROHM CO., LTD recently developed the BU1594GS, a multimedia image processor LSI. This product is a one-chip LSI designed for cellular phone models that are becoming increasingly more functional with advanced features including a camera function. This one-chip LSI, which is ideal for the double-folding models of cellular phones, makes it possible to process major signals in the LCD (liquid crystal display) panel (i.e., the upper panel) of the cellular phone.
Therefore, the BU1594GS greatly reduces the number of inner wires currently necessary of cellular phones. The BU1594GS will functionalize the entire cellular phone system and contribute to the efficient designing of the system. The shipment of BU1594GS product samples started in July (offering a unit sample price of 1,000 yen), and the mass production of the LSI will start in October 2003 at an initial monthly rate of one million units.
Recently, the cellular phone has been featuring advanced functions (e.g., a camera, large-size LCD screen, and strengthened image-processing function) at a growing speed, which makes the internal system including the signal processing line more complicated. These advanced functions greatly increase the burdens of the CPU and DSP, and have been becoming a large obstacle in furthering the enhancement of the functions. The new product is an excellent one-chip LSI that supports the system easily without imposing additional burdens to the CPU or DSP. Conventionally, the CPU, where the image signal is processed and the signal is sent to the LCD panel, once captures the camera signal. Therefore, when the cellular phone is in camera mode, the CPU occupies itself with the processing of the signal. On the contrary, the newly developed LSI works as a dedicated engine, thus operating by temporarily receiving set commands (instructions) from the CPU. This means that the CPU is freed unless the CPU is making command settings, which alleviates the burdens of the CPU. As a merit, the CPU can afford to process other items. The CPU connects to this LSI through a host interface, and the LSI connects to the camera and LCD panel, thus greatly reducing the number of wires in the hinge point. Furthermore, this LSI incorporates an oscillation circuit as countermeasures against EMI (electromagnetic interference), thus downsizing the set and increasing the degree of design freedom of the hinge point.
The one-chip LSI includes the following functions. Camera interface, camera signal filter processing, image signal processing, main LCD interface, sub LCD interface, display memory, memory control, JPEG codec, backlight white LED control, illumination LED control (supporting RGB), and host interface functions.
The LSI has the following main features.
1) Displays 15 frames per second.
2) Power consumption as low as 7 mW while in viewer mode (at the rate of 15 frames per second).
3) JPEG encode/decode functions are built in.
4) The JPEG compression of the VGA-size picture is possible at the rate of 15 frames per second.
5) Real-time image frame composition and overlay processing functions.
6) Provided with an LCD through mode that can be built into existing systems with ease.
The LSI has many other features as well as the above ones.
ROHM has an accumulation of high technology and know-how in the fields of the image signal processing of visual equipment along with the communications signal processing and control of communications equipment. That is the reason ROHM serves as a leader of the industry. ROHM’s new product is the concentration of technologies at highly advanced levels in the respective fields.
ROHM will continue developing new products by predicting the future trend of customers’ needs.
Glossary
Dedicated engineA dedicated driving LSI.
Host interfaceAn interface for a method of communication with the host CPU through a CPU bus. Company Website.