CS4239 Datasheet, PDF (88/98 Pages) Cirrus Logic – CrystalClear™ Portable ISA Audio System

CS4239
CrystalClear^TM Portable ISA Audio System
CS9236 Wavetable Serial Port Interface
A digital interface to the CS9236 Single-Chip Wavetable Music Synthesizer is provided that
allows the CS9236 PCM audio data to be summed on the CS4239 without the need for an
external DAC. This serial port is enabled via the WTEN bit which is located in the Global
Configuration byte in the E²PROM Hardware Configuration data, or C8. The CS9236
Wavetable serial port pins are shared with the CS4610 DSP serial interface. If the CS4610 serial
interface is enabled, the CS9236 interface is not available (SPE takes precedence over WTEN).
SDATA - Wavetable Serial Audio Data, Input
This input supplies the serial audio PCM data to be mixed on the CS4239. The data consists of
left and right channel 16-bit data delineated by LRCLK. This pin should be connected to the
SOUT output pin on the CS9236. This pin should also have a weak pull-down resistor of
approx. 100 kΩ to minimize power-down currents and allow for stuffing options.
LRCLK - Wavetable Serial Left/Right Clock, Input
This input supplies the serial data alignment signal that delineates left from right data. This pin
should be connected to the LRCLK output pin on the CS9236. This pin should also have a
weak pull-down resistor of approx. 100 kΩ to minimize power-down currents and allow for
stuffing options.
MCLK - Wavetable Master Clock, Output (CDROM Enable)
This output supplies the 16.9344 MHz master clock that controls all the timing on the CS9236.
This pin should be connected to the MCLK5I input pin on the CS9236. MCLK can be disabled
in software using the DMCLK bit in C8 in the Control logical device space. DMCLK provides
a partial software power-down mode for the CS9236. At power-up, this pin is an input (with an
internal 100 kΩ pullup) that, when pulled low with a 10 kΩ resistor to SGND, enables the
CDROM interface (in lieu of the upper four ISA address pins). Loading must be limited to
CMOS inputs if this pin has the 10 kΩ resistor attached.
ZVPORT Serial Port Interface
ZSDATA - ZV Port Serial Data, Input
When the ZV port is enabled, ZVEN = 1 in X18, this pin is the serial data input.
ZLRCLK - ZV Port Left/Right Clock, Input
When the ZV port is enabled, ZVEN = 1 in X18, this pin is the Left/Right channel delineation
clock input.
ZSCLK - ZV Port Serial Clock, Input
When the ZV port is enabled, ZVEN = 1 in X18, this pin is the serial data bit clock input.
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