wm8918 Wolfson Microelectronics plc, wm8918 Datasheet - Page 98

• Manufacturer Part Number: wm8918
• Description: Ultra Low Power Dac For Portable Audio Applications
• Manufacturer: Wolfson Microelectronics plc

WM8918
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A list of possible TOCLK rates is provided in Table 62.
Table 62 TOCLK Rates
DAC OPERATION AT 88.2K / 96K
The WM8918 supports DAC operation at 88.2kHz and 96kHz sample rates. This section details
specific conditions applicable to these operating modes. Note that Digital Microphone operation at
88.2kHz or 96kHz is not possible.
For DAC operation at 88.2kHz or 96kHz sample rates, the available clocking configurations are
detailed in Table 63.
DAC operation at these sample rates is achieved by setting the SAMPLE_RATE field to half the
required sample rate (eg. select 48kHz for 96kHz mode). The Digital Microphone DSP must be
disabled (DMICL_ENA = 0 and DMICR_ENA = 0). Note that the DAC_OSR128 and EQ_ENA
registers must be set to 0. ReTune
The SYSCLK frequency is derived from MCLK. The maximum MCLK frequency is defined in the
“Signal Timing Requirements” section.
Table 63 DAC Operation at 88.2kHz and 96kHz Sample Rates
SAMPLE RATE
TOCLK_RATE
88.2kHz
96kHz
1
0
1
0
1
0
1
0
SAMPLE_RATE = 101
CLK_SYS_RATE = 0001 (SYSCLK / fs = 128)
BCLK_DIV = 00010
LRCLK_RATE = 040h
DAC_OSR128 = 0
EQ_ENA = 0
SAMPLE_RATE = 101
CLK_SYS_RATE = 0001 (SYSCLK / fs = 128)
BCLK_DIV = 00010
LRCLK_RATE = 040h
DAC_OSR128 = 0
EQ_ENA = 0
TOCLK_RATE_X4
REGISTER CONFIGURATION
1
1
0
0
1
1
0
0
TM
Mobile can not be used during 88.2kHz or 96kHz operation.
TOCLK_RATE_DIV16
0
0
0
0
1
1
1
1
PD, Rev 4.0, September 2010
FREQ (Hz)
CLOCKING RATIO
SYSCLK = 128 x fs
SYSCLK = 128 x fs
15.625
7.8125
31.25
1000
62.5
500
250
125
Production Data
TOCLK
PERIOD
(ms)
128
16
32
64
1
2
4
8
98