Data Sheet

SWA54 Module Datasheet Rev 1.2
4
A simple low cost implementation of sub-woofer design is shown in Figure 3. The sub amplifier consists of a
PWM chip plus an output stage device, but no external MCU is required as the SWA54-RX module performs
the control function using the I2C master communication port in conjunction with multiple GPIOs. The SWA54
module is configured to accept nominal 5V power from the main application board. An optional reset signal
can be supplied to the SWA54-RX module and I2C or SPI slave communication can be used to control the
module if required.
Several GPIOs can be used to drive LEDs, or to connect to UI buttons. Typically 2 LEDs may be used and 1
button for pairing purposes. Another button could be used, for example, to implement a “bass enhance”
feature. Another GPIO can be used to control the power supply to external system blocks such as the PWM
IC and the output stage. The SWA54-RX module can remain powered up during a standby or low power
operating mode; however, a true power-down mode can be implemented by configuring pin 17
(GPIO15/ADAT2/CEN) to be used as a chip-enable pin that can be used to power down the SKY76303-21.
The SWA54 can also be completely powered down by turning off the main 5V supply.
If the wireless link is lost (ex. when the sound bar is powered down), the SWA54_RX module can, after a
timeout period, power down the amplifier and output stage sections to conserve power and to help meet
Energy Star requirements.
The I2C master port from the SWA54_RX module (pins 5 and 6 on the connector) can communicate, control,
and initialize external audio ICs such as the PWM chip in this example. Other GPIOs can be used to detect
fault conditions (over temperature etc) and notify the module. The audio is routed from the SWA54-RX
module to the amplifier circuit with the I2S output port which can be configured as either a master or a slave
as required. MCLK can also be generated from the SWA54-RX module as a 12.00 MHz clock if required.
SWA54 Module Connections and Interfaces
Signal Type Description
+5.0V Supply
The SWA54 hardware is configured to accept a nominal +5.0V supply.
Reset
Active low reset input. This pin is driven from an open collector/drain device such
that it can be pulled to ground for the active reset state but, when released, must
go to a high impedance state. This pin should not be actively driven high, as the
SKY76303-21 internal reset circuit will not operate correctly.
I2S In Port
The I2S input port can be configured as a master or slave. Consequently BCLK
and LRCK can be either inputs or outputs. In addition, MCLK can be sourced by
the module on pin 16. Since the SKY76303-21
IC contains a sample rate
converter, MCLK is not required to be supplied to the module when it is an I2S
slave. CMOS 3.3V logic levels are used for all I2S signals.
I2S Out Port
The I2S output port can be configured as a master or slave. Consequently BCLK
and LRCK can be either inputs or outputs. In addition, MCLK can be sourced by
the module on pin 16. Since the SKY76303-21
IC contains a sample rate
converter, MCLK is not required to be supplied to the module when it is an I2S
slave. CMOS 3.3V logic levels are used for all I2S signals.
I2C Slave Port
The I2C slave port can be used for external host communication and for module
testing. It is assumed that external pull up resistors are connected at the I2C
master communicating with the module.