SGTL5000XNAA3R2 Datasheet, PDF (19/68 Pages) Freescale Semiconductor, Inc – Low Power Stereo Codec with Headphone Amp

FUNCTIONAL DEVICE OPERATION
FUNCTIONAL INTERNAL BLOCK DESCRIPTION
PCM Mode
The I²S port can also be configured in PCM mode (also
known as DSP mode). This mode is provided to allow
connectivity to external devices such as Bluetooth modules.
PCM mode differs from other interface formats presented in
I2S, Left Justified, and Right Justified Modes, in that the
frame clock (I2S_LRCLK) does not represent a different
channel when high or low. Instead, it is a bit-wide pulse that
marks the start of a frame. Data is aligned such that the left
channel data is immediately followed by right channel data.
Zero padding is filled in for the remaining bits. The data and
frame clock may be configured to clock in on the rising or
falling edge of Bit Clock.
PCM Format A is a format in which the data word begins
one SCLK bit following the I2S_LRCLK transition, as in I²S
Mode. PCM Format B is a format in which the data word
begins after the I2S_LRCLK transition, as in Left Justified.
In slave mode, the pulse width of the I2S_LRCLK does not
matter. The pulse can range from one cycle high to all but one
cycle high. In master mode, it is driven one cycle high.
Figures 11 shows a functional drawing of the different
formats in master mode.
PCM Format A
CHIP_I2S0_CTRL = 0x01F4
(SCLKFREQ = 1; MS = 1; SCLK_INV = 1; DLEN = 3; I2S_MODE = 2; LRALIGN = 0)
I2S_LRCLK
I2S_SCLK
I2S_DIN, DOUT
Ln L(n-1)
L0 Rn R(n-1)
R1 R0 Ln L(n-1)
L0 Rn R(n-1)
R1 R0
PCM Format B
CHIP_I2S0_CTRL = 0x01F6
(SCLKFREQ = 1; MS = 1; SCLK_INV = 1; DLEN = 3; I2S_MODE = 2; LRALIGN = 1)
I2S_LRCLK
I2S_SCLK
I2S_DIN, DOUT
Ln L(n-1)
L0 Rn R(n-1)
R0 Ln L(n-1)
L0 Rn R(n-1)
R0
Figure 11. PCM Formats
DIGITAL AUDIO PROCESSING
The SGTL5000 contains a digital audio processing block
(DAP) connected to the source select switch. The digitized
signal from the source select switch can be routed into the
DAP block for audio processing. The DAP has the following
5 sub blocks:
• Dual Input Mixer
• Freescale Surround
• Freescale Bass Enhancement
• 7-Band Parameter EQ / 5-Band Graphic EQ / Tone Control
(only one can be used at a time)
• Automatic Volume Control (AVC)
The block diagram in Figure 12 shows the sequence in
which the signal passes through these blocks.
Analog Integrated Circuit Device Data
Freescale Semiconductor
SGTL5000
19