Accelerator makes cell phones snappy
By Brian Dipert - March 20, 2003
Judging from the JPEG encoder built into the MediaQ MQ2100, the company buys into market-analyst predictions that lots of folks will soon replace their cell phones with units containing built-in digital still cameras and videocameras (Picture). The chip is an upgrade of the MQ2074, and it includes a 2-D-graphics accelerator functionally identical to the one in the MQ1188 and handy for handheld gaming, mapping, and other visual applications (see "Power-stingy peripheral chips provide partitioning options," EDN, Nov 28, 2002, pg 14). It also incorporates a CCIR656-compliant camera interface with support for YUV422-to-RGB565 conversion, horizontal decimation with pixel averaging and programmable lowpass filtering, and vertical decimation. Reflecting its phone, not PDA, focus, the MQ2100 embeds a smaller, 160-kbyte SRAM buffer than the one in the MQ1188. This buffer provides 176×220-pixel resolution at 16-bit-per-pixel color depth (double-buffered) or 240×320-pixel—that is, QVGA—resolution at 16 bit-per-pixel color depth (single-buffered).
MediaQ estimates that, in typical operating modes at refresh rates as fast as 15 frames/sec, the MQ2100 will draw less than 5 mW of power; various chip subsystems operate at 1.5, 1.8, and 2.5V. The hardware JPEG-baseline-encoder core employs fixed Huffman tables, can operate as fast as 30 frames/sec, and supports resolutions as high as VGA: 640×480 pixels. It also includes a 4:2:2-to-4:2:0 input chroma filter and supports black-level and contrast correction, input scaling, a scaled preview image, and floating-point quantization. The MQ2100 supports a range of STN (supertwist-nematic) and TFT (thin-film-transistor) color LCDs, including LTPS (low-temperature-polysilicon) and Sharp's ULC (ultra-low-power-consumption) variants, and it comprehends NEC's Mobile current-mode-advanced-differential-signaling serial interface. It offers 16-level frame-rate control and as much as 4-bit spatial dithering on STNs, with error diffusion. Partial display-update mode, power-sequencing support in hardware, and PWM outputs for brightness and contrast control complete the picture. The MQ2100 costs $5.75 (10,000) in a 144-bump BGA package and is in production.
MediaQ, 1-408-733-0088, www.mediaq.com.