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Toshiba's MDDI-compliant LCD Controller for Cell Phones

Toshiba America Electronic Components, Inc. has announced the introduction of the world's first MDDI-compliant LCD controller optimized for cell phones equipped with high-resolution Video Graphics Array (VGA) LCD displays.

Dubbed the MDDI LCD Bridge and designated TC358720XBG, the highly integrated, single-chip device is suited for the new generation of advanced multimedia cell phones with MDDI interfaces, including 3G cellular handsets. It has a high-speed serial digital packet host interface that supports throughputs of up to 400Mbps by using two low-voltage differential signal pairs.

The MDDI LCD Bridge takes cell phone display resolution to the level of high-definition with support for VGA and W-QVGA LCDs. It optimizes low-power data transfers within cell phones, including video data transfers, through direct connection to the MDDI interface of QUALCOMM's Mobile Station Modem (MSM) baseband LSI. Its design also integrates 8-megabits of embedded DRAM to improve color image quality.

Equipped with an RGB interface plus an MPU interface, the device can control both a primary panel and a secondary panel. The image data needed to display images on two panels is stored in the embedded DRAM and only the updated parts of the display data need to be transferred from the baseband. When displaying still images, data need not be transferred from the baseband and this advance reduces the power consumption of the entire cell phone. The moving-image display function is supported on both the primary and secondary panels, and provides a mechanism for transferring image data to match the LCD display refresh timing. With the primary panel, it is possible to display VGA-size moving images and update only the locations displaying QVGA-size moving images, such as terrestrial digital broadcasts. This simplifies and reduces power consumption from baseband processing.

With the Toshiba "magic square algorithm", an RGB666 18-bit LCD panel can produce a display equivalent to that of an RGB888 24-bit LCD panel with up to 16-million colors. In addition, the algorithm enables display of 8-bit gray scale images even if the LCD panel only has a 6-bit gray scale capacity. The chip has independent 8-bit lookup table format gamma correction circuits for each color. The lookup table format converts 8-bit input into 8-bit output. This function permits fine adjustments to the brightness, even in LCD panels with a limited range of tones.

Main Features:
* Compatible with the MDDI standard, supporting high-speed data transfer rates up to 400Mbps, and directly connectible to the MDDI interface of QUALCOMM's MSM baseband solutions

* Integrates 8Mb embedded DRAM with a primary frame buffer for the primary display and a secondary frame buffer for the secondary display

* Display interface supports two panels with a maximum VGA LCD size:
- Supports primary displays up to VGA size with a 60Hz refresh rate: RGB565, RGB666 format and 16-/18-bit RGB interface displays
- Supports secondary display up to QCIF+ size: RGB565, RGB666 and RGB888 format, 8-/16-/18-bit MPU interface
- Has programmable gamma correction and RGB format conversion
- Supports 180-degree rotation and mirroring

* Uses Toshiba's patented "magic square algorithm" technology to interpolate RGB666 to pseudo RGB888 image data with up to 16 million colors

* Uses SPI and I2C to control LCD panels and peripheral circuits

* Has PWM control output for adjusting LCD backlight brightness with two channels enabling independent brightness adjustments of the primary panel and the secondary panel

* Has up to 10 GPIO ports; the additional pins at the upper clamshell chassis allow I/O expansion for baseband processors.



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