The AD1816A SoundPort Controller is a single chip Plug and Play multimedia audio subsystem for concurrently processing multiple digital streams of 16-bit stereo audio in personal computers. The AD1816A maintains full legacy compatibility with applications written for SoundBlaster Pro and AdLib, while servicing Microsoft PC 97 application requirements. The AD1816A includes an internal OPL3 compatible music synthesizer, Phat Stereo circuitry for phase expanding the analog stereo output, an MPU-401 UART, joystick interface with a built-in timer, a DSP serial port and two I2S serial ports. The AD1816A on-chip Plug and Play routine provides configuration services for all integrated logical devices. Using an external E2PROM allows the AD1816A to decode up to two additional external user-defined logical devices such as modem and CD-ROM.