Section 10
Direct Memory Access Controller (DMAC)
Rev. 0.50 May 18, 2006 Page 407 of 1588
REJ09B0313-0050
10.4.3 Channel
Priority
When the DMAC receives simultaneous transfer requests on two or more channels, it selects a
channel according to a predetermined priority order. Three modes (fixed mode 1, fixed mode 2,
and round-robin mode) are selected using the PR1 and PR0 bits in DMAOR.
(1) Fixed
Mode
In fixed modes, the priority levels among the channels remain fixed. There are two kinds of fixed
modes as follows:
Fixed mode 1: CH0 > CH1 > CH2 > CH3 > CH4 > CH5 > CH6 > CH7
Fixed mode 2: CH0 > CH4 > CH1 > CH5 > CH2 > CH6 > CH3 > CH7
These are selected by the PR1 and PR0 bits in the DMA operation register (DMAOR).
(2) Round-Robin
Mode
Each time one unit of word, byte, longword, or 16 bytes is transferred on one channel, the priority
order is rotated. The channel on which the transfer was just finished is rotated to the lowest of the
priority order among the four round-robin channels (channels 0 to 4). The priority of the channels
other than the round-robin channels (channels 0 to 4) does not change even in round-robin mode.
The round-robin mode operation is shown in figure 10.3. The priority in round-robin mode is CH0
> CH1 > CH2 > CH3 > CH4 > CH5 > CH6 > CH7 immediately after a reset.
When the round-robin mode has been specified, do not concurrently specify cycle steal mode and
burst mode as the bus modes of any two or more channels.
Summary of Contents for Single-Chip Microcomputer SH7203
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Page 52: ...Section 1 Overview Rev 0 50 May 18 2006 Page 22 of 1588 REJ09B0313 0050 ...
Page 98: ...Section 2 CPU Rev 0 50 May 18 2006 Page 68 of 1588 REJ09B0313 0050 ...
Page 128: ...Section 4 Clock Pulse Generator CPG Rev 0 50 May 18 2006 Page 98 of 1588 REJ09B0313 0050 ...
Page 200: ...Section 6 Interrupt Controller INTC Rev 0 50 May 18 2006 Page 170 of 1588 REJ09B0313 0050 ...
Page 242: ...Section 8 Cache Rev 0 50 May 18 2006 Page 212 of 1588 REJ09B0313 0050 ...
Page 400: ...Section 9 Bus State Controller BSC Rev 0 50 May 18 2006 Page 370 of 1588 REJ09B0313 0050 ...
Page 696: ...Section 13 Watchdog Timer WDT Rev 0 50 May 18 2006 Page 666 of 1588 REJ09B0313 0050 ...
Page 726: ...Section 14 Realtime Clock RTC Rev 0 50 May 18 2006 Page 696 of 1588 REJ09B0313 0050 ...
Page 876: ...Section 17 I2 C Bus Interface 3 IIC3 Rev 0 50 May 18 2006 Page 846 of 1588 REJ09B0313 0050 ...
Page 1054: ...Section 21 D A Converter DAC Rev 0 50 May 18 2006 Page 1024 of 1588 REJ09B0313 0050 ...
Page 1294: ...Section 24 LCD Controller LCDC Rev 0 50 May 18 2006 Page 1264 of 1588 REJ09B0313 0050 ...
Page 1386: ...Section 26 I O Ports Rev 0 50 May 18 2006 Page 1356 of 1588 REJ09B0313 0050 ...
Page 1512: ...Section 30 List of Registers Rev 0 50 May 18 2006 Page 1482 of 1588 REJ09B0313 0050 ...
Page 1598: ...Section 31 Electrical Characteristics Rev 0 50 May 18 2006 Page 1568 of 1588 REJ09B0313 0050 ...
Page 1606: ...Appendix Rev 0 50 May 18 2006 Page 1576 of 1588 REJ09B0313 0050 ...
Page 1618: ...Rev 0 50 May 18 2006 Page 1588 of 1588 REJ09B0313 0050 ...
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