AD1846

a FEATURES Low Cost, Pin- and Register-Compatible Alternative to AD1848 Single-Chip Integrated ∑∆ Digital Audio Stereo Codec Supports the Microsoft Windows Sound System* Multiple Channels of Stereo Input and Output Analog and Digital Signal Mixing Programmable Gain and Attenuation On-Chip Signal Filters Digital Interpolation and Decimation Analog Output Low-Pass Sample Rates from 5.5 kHz to 48 kHz 68-Lead PLCC Package Operation from +5 V Supply Byte-Wide Parallel Interface to ISA and EISA Buses Supports One or Two DMA Channels and Programmed I/O PRODUCT OVERVIEW Low Cost Parallel-Port 16-Bit SoundPort Stereo Codec AD1846 It provides a direct, byte-wide interface to both ISA (“AT”) and EISA computer buses for simplified implementation on a computer motherboard or add-in card. The AD1846 generates enable and direction controls for IC buffers such as the 74_245. The AD1846 SoundPort Stereo Codec supports a DMA request/grant architecture for transferring data with the host computer bus. One or two DMA channels can be supported. Programmed I/O (PIO) mode is also supported for control register accesses and for applications lacking DMA control. Two input control lines support mixed direct and indirect addressing of twenty-one internal control registers over this asynchronous interface. External circuit requirements are limited to a minimal number of low cost support components. Anti-imaging DAC output filters are incorporated on-chip. DAC dynamic range exceeds 80 dB over the 20 kHz...