Rainbow Electronics MAX9867 - Manual (Page 25)

MAX9867
Ultra-Low Power Stereo Audio Codec
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BITS FUNCTION
Exact Integer Modes
Allows integer sampling for specific PCLK (prescaled MCLK) frequencies and 8kHz or 16kHz sample rates.
FREQ[3:0] PCLK (MHz) LRCLK (kHz) PCLK/LRCLK
0x00 Normal or PLL mode
0x1–0x7 Reserved Reserved Reserved
0x8
0x9 12
12 8
16
1500
750
0xA
0xB 13
13 8
16
1625
812.5
0xC
0xD 16
16 8
16
2000
1000
0xE
0xF
19.2
19.2 8
16
2400
1200
FREQ
Modes 0x8–0xF are available in either master or slave mode. In slave mode, if the indicated PCLK/LRCLK ratio
cannot be guaranteed, use PLL mode instead.
PLL
PLL Mode Enable
0 = Valid for slave and master mode. The frequency of LRCLK is set by the NI divider bits. In master mode, the
MAX9867 generates LRCLK using the specified divide ratio. In slave mode, the MAX9867 expects an
LRCLK as specified by the divide ratio.
1 = Valid for slave mode only. A digital PLL locks on to any externally supplied LRCLK signal.
Rapid Lock Mode
To enable rapid lock mode, set NI to the nearest desired ratio and set NI[0] = 1 before enabling the interface.
NI
Normal Mode LRCLK Divider
When PLL = 0, the frequency of LRCLK is determined by NI. See Table 5 for common NI values.
NI = (65536 x 96 x f
LRCLK
)/f
PCLK
f LRCLK = LRCLK frequency
f PCLK = Prescaled MCLK internal clock frequency (PCLK)
LRCLK > 24kHz is only valid for MODE = 0 (stereo audio mode). MODE = 1 (voice mode) requires LRCLK ≤
24kHz.
Table 4. Clock Control Registers (continued)
LRCLK (kHz)
MCLK (MHz)
PSCLK 8 16 24 32 44.1 48
11.2896 01 0x116A 0x22D4 0x343F 0x45A9 0x6000 0x687D
12 01 0x1062 0x20C5 0x3127 0x4189 0x5A51 0x624E
12.288 01 0x1000 0x2000 0x3000 0x4000 0x5833 0x6000
13 01 0x0F20 0x1E3F 0x2D5F 0x3C7F 0x535F 0x5ABE
19.2 01 0x0A3D 0x147B 0x1EB8 0x28F6 0x3873 0x3D71
24 10 0x1062 0x20C5 0x1893 0x4189 0x5A51 0x624E
26 10 0x0F20 0x1E3F 0x16AF 0x3C7F 0x535F 0x5ABE
27 10 0x0E90 0x1D21 0x15D8 0x3A41 0x5048 0x5762
Note: Bolded values are exact integers that provide maximum full-scale performance.
Table 5. Common NI Values