cs4237b Cirrus Logic, Inc., cs4237b Datasheet - Page 79

• Manufacturer Part Number: cs4237b
• Description: Crystalclear Advanced Audio System With 3d Sound
• Manufacturer: Cirrus Logic, Inc.

For backwards compatibility with analog-mixed
wavetable devices, I18 and I19 in the WSS logi-
cal device can be remapped to control the
volume of the Wavetable serial port. Remapping
is controlled through the WTRMD bit in X4 reg-
ister. When WTEN = 1, and WTRMD = 0,
writes to I18 and I19 are remapped to X16 and
X17 respectively. When remapping is enabled,
the LINE analog input volume is controlled
thr ough X0/1. When WTRMD = 1, the
Wavetable Serial Port volume is only controlled
through X16/17.
WSS CODEC SOFTWARE DESCRIPTION
The WSS Codec must be in Mode Change En-
able Mode (MCE=1) before any changes to the
Interface Configuration register (I9) or the Sam-
ple Frequency (lower four bits) in the Fs &
Playback Data Format registers (I8) are allowed.
The actual audio data formats, which are the up-
per four bits of I8 for playback and I28 for
capture, can be changed by setting MCE (R0) or
PMCE/CMCE (I16) high. The exceptions are
CEN and PEN which can be changed "on-the-
fly" via programmed I/O writes. All outstanding
DMA transfers must be completed before new
values of CEN or PEN are recognized.
DS213PP4
MIDOUT
BRESET
Figure 13. CS9236 Wavetable Serial Port Interface
SDATA
LRCLK
MIDIN
MCLK
100
100k
Midi In
Joystick Connector
100k
Midi Out
MCLK5I
LRCLK
SOUT
RST
PDN
MIDI_IN
CS9236
XTAL3I
Calibration
The WSS Codec has four different calibration
modes. The selected calibration occurs whenever
the Mode Change Enable (MCE, R0) bit goes
form 1 to 0.
The completion of calibration can be determined
by polling the Auto-Calibrate In-Progress bit in
the Error Status and Initialization register (ACI,
I11). This bit will be high while the calibration is
in progress and low once completed. Transfers
enabled during calibration will not begin until
the calibration cycle has completed. Since the
part always operates at 44.1 kHz internally, all
calibration times are based on 44.1 kHz sample
periods.
The Calibration procedure is as follows:
1) Place the WSS Codec in Mode Change
2) Set the CAL1,0 bits in the Interface Configura-
3) Return from Mode Change Enable by reset-
4) Wait until 80h NOT returned
5) Wait until ACI (I11) cleared to proceed
NO CALIBRATION (CAL1,0 = 00)
This is the fastest mode since no calibration is
performed. This mode is useful for games which
require the sample frequency be changed
quickly. This mode is also useful when the codec
is operating full-duplex and an ADC data format
change is desired. This is the only calibration
mode that does not affect the DACs (i.e. mute
the DACs). The No Calibration mode takes zero
sample periods.
Enable using the MCE bit of the Index Ad-
dress register (R0).
tion register (I9).
ting the MCE bit of the Index Address
register (R0).
CS4237B
79