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SH7065 Datasheet, PDF (354/941 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH RISC engine Family/SH7000 Series
Section 9 Direct Memory Access Controller (DMAC)
Figure 9.4 shows the changes in priority levels when transfer requests are issued simultaneously
for channels 0 and 3, and channel 1 receives a transfer request during a transfer on channel 0. The
operation of the DMAC in this case is as follows.
1. Transfer requests are issued simultaneously for channels 0 and 3.
2. Since channel 0 has a higher priority level than channel 3, the channel 0 transfer is executed
first (channel 3 is on transfer standby).
3. A transfer request is issued for channel 1 during the channel 0 transfer (channels 1 and 3 are on
transfer standby).
4. At the end of the channel 0 transfer, channel 0 shifts to the lowest priority level.
5. At this point, channel 1 has a higher priority level than channel 3, so the channel 1 transfer is
started (channel 3 is on transfer standby).
6. At the end of the channel 1 transfer, channel 1 shifts to the lowest priority level.
7. The channel 3 transfer is started.
8. At the end of the channel 3 transfer, the channel 3 and channel 2 priority levels are lowered,
giving channel 3 the lowest priority.
Rev. 5.00 Sep 11, 2006 page 332 of 916
REJ09B0332-0500