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Section 22 Renesas SPDIF Interface
Page 1154 of 2108 R01UH0134EJ0400 Rev. 4.00
Sep 24, 2014
SH7262 Group, SH7264 Group
Figure 22.4 shows the block format, which consists of 192 continuous frames. One block begins at
the starting frame (preamble B) and ends at the 192nd frame (frame 191), and the preamble is used
to identify all subframes. Each block has a total of 384 subframes, which are classified into three
categories: subframe 0 indicating the beginning of a new block, subframe 1 (usually the channel
1), and subframe 2 (usually the channel 2). Usually, the music data sent and received by the
SPDIF is continuous so that continuous blocks appear.
BWM WMW
Channel 1
0 1 191 1
Channel 2 Channel 1 Channel 2 Channel 1 Channel 2
B
Channel 1
M
0
Channel 1
B = Start of block preamble
W = Channel 2 preamble
M = Channel 1 preamble but not start of block
Figure 22.4 Block Format
Table 22.2 shows the binary values of the Renesas SPDIF preambles. The polarity of these
preambles differs depending on the status of the preceding symbol (parity bit).
Table 22.2 Binary Preamble Values
Preamble Preceding Symbol's Status = 0 Preceding Symbol's Status = 1
B 11101000 00010111
M 11100010 00011101
W 11100100 00011011
Note: As shown in figure 22.3, the even parity bit at time slot 31 of a subframe determines the
type of a preamble for one cycle of transmission. Usually, therefore, any one is selected
from the set states that are sent through the Renesas SPDIF. However, IEC60958 requires
decoding both types in view of connection with the preamble polarity reversed; the Renesas
SPDIF has preambles decoded according to table 22.2.
Channel status information is encoded at the rate of one bit per subframe, making the channel
status information per block have a total of 192 bits for each of subframes 1 and 2. For the format
of the channel status, refer to the IEC 60958 standard.