Cirrus Logic AN302 - Manual

Copyright © Cirrus Logic, Inc. 2006
(All Rights Reserved)
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Interfacing the CS5368/66/64 and CS4364/65/84/85 in
TDM Mode
The CS4364, CS4365, CS4384 and CS4385 digital-to-analog converters and the CS5368, CS5366 and the CS5364
analog-to-digital converters support a multi-channel Time Division Multiplexed (TDM) data interface. The implemen-
tations make use of a serial clock, Frame Sync, and serial data as described in the Cirrus Logic Applications Note
AN301. However, the CS4364/65/84/85 is somewhat limited in regards to the allowable width of the Frame Sync
when compared to the CS5368/66/64. As shown in
Figure 1 , the CS4364/65/84/85 requires a Frame Sync pulse
width which is equivalent to one period of the serial clock. The allowable pulse width for CS5368/66/64 is much more
flexible in that it is only limited by a required low time of one period of the serial clock period when operated in Slave
Mode as shown in
Figure 2 .
The CS5368/66/64 also has the capability to provide the system serial clock and Frame Sync for the TDM interface
when operated in Master mode. However, the pulse width of the generated Frame Sync is equivalent to 50% of the
frame period, as shown in
Figure 3 , which is incompatible with the CS4364/65/84/85.
A compatible TDM mode for the CS4364/65/84/85 and CS5368/66/64 exists when operated in Slave mode and the
system clocking source generates a Frame Sync pulse width equivalent to a single period of the serial clock, as
shown in
Figure 1 .
Figure 1. CS4364/65/84/85 TDM Clocking Requirements
Figure 2. CS5368/66/64 TDM Mode as Sytem Clock Slave
Figure 3. CS5368/66/64 TDM Mode as System Clock Master
SCLK
Channel 5 Channel 6 SDATA Channel 1 Channel 2
32 sclks 32 sclks 32 sclks 32 sclks 32 sclks 32 sclks
Channel 7 Channel 8
32 sclks 32 sclks
Channel 4 Channel 3
Frame
FS
FS
SCLK
SDATA
Frame
Channel 5 Channel 6 Channel 1 Channel 2
32 sclks 32 sclks 32 sclks 32 sclks 32 sclks 32 sclks
Channel 7 Channel 8
32 sclks 32 sclks
Channel 4 Channel 3
SCLK
Channel 5 Channel 6 SDATA Channel 1 Channel 2
32 sclks 32 sclks 32 sclks 32 sclks 32 sclks 32 sclks
Channel 7 Channel 8
32 sclks 32 sclks
FS
Channel 4 Channel 3
Frame
AUGUST
'
06
AN302REV1
AN302