STA559BW View Datasheet(PDF) - STMicroelectronics

Part Name

Description

View to exact match

STA559BW

5 V, 2 A, 2.1 channel high-efficiency digital audio system Sound Terminal®

STMicroelectronics 

Register description

STA559BW

The PWDN register is used to place the IC in a low-power state. When PWDN is written

as 0, the output begins a soft-mute. After the mute condition is reached, EAPD is asserted

to power down the power-stage, then the master clock to all internal hardware expect the

I²C block is gated. This places the IC in a very low power consumption state.

External amplifier power down

Bit R/W

7

R/W

Table 49. External amplifier power down

RST

Name

Description

0

EAPD

0: external power stage power down active

1: normal operation

The EAPD register directly disables/enables the internal power circuitry.

When EAPD = 0, the internal power section is placed in a low-power state (disabled). This

register also controls the FFX4B / EAPD output pin when OCFG = 10.

6.2

Volume control registers (addr 0x06 - 0x0A)

The volume structure of the STA559BW consists of individual volume registers for each

channel and a master volume register that provides an offset to each channels volume

setting. The individual channel volumes are adjustable in 0.5 dB steps from +48 dB

to -80 dB.

As an example if C3VOL = 0x00 or +48 dB and MVOL = 0x18 or -12 dB, then the total gain

for channel 3 = +36 dB.

The channel mutes provide a “soft mute” with the volume ramping down to mute in

4096 samples from the maximum volume setting at the internal processing rate

(approximately 96 kHz).

A “hard (instantaneous) mute” can be obtained by programming a value of 0xFF (255) in

any channel volume register. When volume offsets are provided via the master volume

register any channel whose total volume is less than -80 dB is muted.

All changes in volume take place at zero-crossings when ZCE = 1 (Configuration register E

(addr 0x04) on page 30) on a per channel basis as this creates the smoothest possible

volume transitions. When ZCE = 0, volume updates occur immediately.

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