Cirrus Logic CS4365 - Manual (Page 24)

24 DS670F2
CS4365
4.3.1 OLM #1
OLM #1 serial audio interface format operates in Single-, Double-, or Quad-Speed Mode and will slave to
SCLK at 128 Fs. Six channels of MSB first 20-bit PCM data are input on SDIN1.
4.3.2 OLM #2
OLM #2 serial audio interface format operates in Single-, Double-, or Quad-Speed Mode and will slave to
SCLK at 256 Fs. Six channels of MSB first 24-bit PCM data are input on SDIN1.
4.4 Oversampling Modes
The CS4365 operates in one of three oversampling modes based on the input sample rate. Mode selection
is determined by the M4, M3 and M2 pins in Hardware Mode or the FM bits in Software Mode. Single-Speed
mode supports input sample rates up to 50 kHz and uses a 128x oversampling ratio. Double-Speed Mode
supports input sample rates up to 100 kHz and uses an oversampling ratio of 64x. Quad-Speed Mode sup-
ports input sample rates up to 200 kHz and uses an oversampling ratio of 32x.
The auto-speed mode detect feature allows for the automatic selection of speed mode based off of the in-
coming sample rate. This allows the CS4365 to accept a wide range of sample rates with no external inter-
vention necessary. The auto-speed mode detect feature is available in both hardware and Software Mode.
LRCK
SCLK
Left Channel
Right Channel
SDINx 6 5 4 3 2 1 0 9 8 7 15 14 13 12 11 10 1 0 6 5 4 3 2 1 0 9 8 7 15 14 13 12 11 10 17 16 17 16
32 clocks
Figure 13. Format 5 - Right-Justified 18-bit Data
LRCK
SCLK
LSB MSB
20 clks
64 clks 64 clks
LSB MSB LSB MSB LSB MSB LSB MSB LSB MSB MSB
DAC_A1
20 clks 20 clks 20 clks 20 clks 20 clks
Left Channel Right Channel
SDIN1
DAC_A2 DAC_A3 DAC_B1 DAC_B2 DAC_B3
Figure 14. Format 8 - One-Line Mode 1
L S B M S B
24 clks
128 clks
LS B M SB LS B M S B LS B M S B L S B M S B LS B M SB M S B
D AC _A 1
2 4 clks 2 4 clks 2 4 clks 24 clks 2 4 clks
Left C hannel Right C hannel
128 clks
LRCK
SC LK
SD IN1
D A C _A2 D AC _A3 D A C _B 1 D A C _B 2 D A C _B 3
Figure 15. Format 9 - One-Line Mode 2