Theory of Operation 4-23
4.3.2.6 ESS1688 Audio Controller
ESS Technology has developed the ES1688 AudioDrive, a single chip solution for adding 16-bit
stereo audio and four-oper ator FM music synthesis to personal computers. It has integrated all t he
major blocks of audio in to a single chip that can be designed into a motherboard, notebook PC,
add-on card, or integrated onto other peripheral cards such as VGA, LAN, I/O, etc.
The ES1688 AudioDrive can record, compress, and playback voice, sound and music with built-in
mixer controls. It consists of an embedded microprocessor, 16-bit stereo A/D and D/A, 20-voice
FM music synthesizer, MIDI serial port compatible with MPU401 UART mode, DMA control,
and ISA bus interface logic. A DSP serial interface allows an external DSP to take over analog
resources such as the D/A or A/D converters. Control of I/O address, DMA, and interrupt
selection can be by jumper or by control of system software. Interface to analog inputs is
extremely simple. There are stereo inputs for CD-audio, line-in, and an external music synthesis
chip, and a mono microphone input to an internal pre-amp. A digital PC speaker input is
converted to an analog signal with volume control and is available as an analog output signal.
Address decode outputs simplify int erfacing to a game port. Advanced power management
features such as Suspend/Resume and partial power-down are supported.
The ES1688 AudioDrive is compatible with Sound Blaster PRO version 3.01 voice and music
functions as documented in the Sound Blaster Series Developer Kit. The ES1688 is pin-compatible
with the ES688 AudioDrive.