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Section 23 CD-ROM Decoder
Page 1242 of 2108 R01UH0134EJ0400 Rev. 4.00
Sep 24, 2014
SH7262 Group, SH7264 Group
23.4 Operation
23.4.1 Endian Conversion for Data in the Input Stream
Stream data must be input to the core of the CD-ROM decoder in order according to the CD-ROM
data format specifications. In some systems, however, the order of the data from the serial sound
interface may have to be changed or the data will have been padded before transfer. To cope with
this, the stream data input control section is capable of swapping the order of the data and
preventing the input of padding data to the core of the CD-ROM decoder. These functions are
controlled through the serial sound interface data control register (SSI).
Figure 23.6 shows a case where the upper and lower 16 bits of the data, consisting of padding data
plus the first 2 bytes of sync code, that is, H'000000FF, are swapped (H'00FF0000) and input to
the CD-ROM decoder as the stream data.
Core of CD-ROM decoder
BUFEND1[1:0] = 00
BYTEND = 0
H'0000
BUFEND0[1:0] = 01
H'00FF
H'00FF
H'00FF
STRMDIN0
STRMDIN2
H'00 H'00 H'00 H'FF
Figure 23.6 Example of Padded Stream Data Control by the SSI Register