Introduction
1.2.6 Power Management
The device is designed for power sensitive applications and incorporates design features to minimise power consumption. Typical power consumption for the device is 0.3 Watts. A power down mode allows power savings to be made when the device is not in use - e.g. in conjunction with a battery powered LCD system. Additional power sensitive features include the powering down of functions of the device currently not in use, such as the video DACs, sound DACs and the LCD grey scaler. In addition the palette design has been segmented such that only one eighth of the palette is enabled and docked at any one time.
1.2.7 On-Chip Sound System
The VIDC20 supports two systems - an 8-bit (logarithmic) system using an internal dedicated DAC, featuring up to eight channels each with its own stereo position, and a 32-bit serial sound output suitable for driving external CD DACs.
In the 8-bit mode the device can work with 1,2,4 or 8 stereo channels, using time division multiplexing to synthesise left and right outputs. The sample rate is programmable through the Sound Frequency Register.
Enhanced 32-bit stereo sound is offered by the serial sound output which consists of a three pin serial interface. Each 32-bits sample consists of 16 bits for the left channel and 16 bits for the right channel.