Sharp LH79524 - Figure 10-2. TI SSP Frame Format; Theory of Operation

LH79524/LH79525 User’s Guide I
2
S Converter
Version 1.0 10-3
10.1 Theory of Operation
10.1.1 Conversion
The SSP-to-I
2
S converter converts a data stream from the TIDSP format to the I
2
S for-
mat on transmit or from I
2
S format to TI DSP format on receive. The TI DSP format is sup-
ported by the SSP block and is fully described in the SSP Chapter. The I
2
S format is an
audio standard made popular by Phillips Semiconductor. Figure 10-2 shows the Texas
Instruments DSP format for continuous transfers.
The I
2
S frame format is described in the I
2
S Bus specification published by Phillips Semi-
conductors. An example I
2
S transaction is shown in Figure 10-3.
Figure 10-2. TI SSP Frame Format
Figure 10-3. I
2
S Format
SSPCLK
SSPFRM
SSPTX/
SSPRX
LSB
MSB
4 to 16 BITS
LH79525-77
MSB
SCK
WS
SD
MSBLSB
WORD n+1
RIGHT CHANNEL
WORD n
LEFT CHANNEL
WORD n-1
RIGHT CHANNEL
LH79525-94