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Section 23 CD-ROM Decoder
Page 1258 of 2108 R01UH0134EJ0400 Rev. 4.00
Sep 24, 2014
SH7262 Group, SH7264 Group
23.6.6 Note on Stream Data Transfer (1)
When reading of the stream data is slower than writing of the stream data, the buffer of the CD-
ROM decoder will overflow. This causes the CD-ROM decoder to be abnormally stopped.
Caution is required in writing and reading of the stream data. Sample combinations of stream data
transfer settings are shown below.
Table 23.4 Sample Combinations of Stream Data Transfer Settings
Stream Input Stream Output
LW/cycle-stealing transfer by
direct memory access controller
(without padding)
(1) 16-byte/cycle-stealing transfer by direct memory access
controller (16 bytes*)
(2) Burst transfer by direct memory access controller (16 bytes*,
longword, word)
LW/cycle-stealing transfer by
direct memory access controller
(with padding)
(1) Cycle-stealing transfer by direct memory access controller
(16 bytes*, longword)
(2) Burst transfer by direct memory access controller (16 bytes*,
longword, word)
LW write by CPU (1) Cycle-stealing transfer by direct memory access controller
(16 bytes*, longword, word)
(2) Burst transfer by direct memory access controller (16 bytes*,
longword, word)
Note: * Set bit 25 in the DMA channel control register (CHCR_n) to 1, as well as making the
regular settings for 16-byte transfer.
23.6.7 Note on Stream Data Transfer (2)
When reading the stream data, be sure to use either the direct memory access controller or the
CPU. If both the direct memory access controller and the CPU are used for reading, the stream
data may not be recognized as being in the CD-ROM format.