Difference In Operation Due To The Transfer Size - Renesas RZ/A Series User Manual

RZ/A1L Group, RZ/A1LU Group, RZ/A1LC Group
9.7.10

Difference in Operation Due to the Transfer Size

(1) When the Source Transfer Size Is Smaller
When the read of data equivalent to the destination data size is completed, the data is written to the destination.
The following figure shows a timing chart where the source transfer size is 8 bits and the destination transfer size is 32
bits (in the case of rising edge detection).
DMAREQ[0]
DMAACK[0]
REQD
SDS
DDS
CRTB_n
DMA Transfer
Figure 9.25 When the Source Transfer Size Is Smaller (LVL = 0, HIEN = 1, REQD = 0, SDS < DDS in CHCFG_n)
(2) When the Destination Transfer Size Is Smaller
Since the source transfer size is larger, multiple destination writes occur after a single source read. The following figure
shows a timing chart where the source transfer size is 64 bits and the destination transfer size is 16 bits (in the case of
rising edge detection) (1 is set in REQD of the CHCFG_n register).
DMAREQ[0]
DMAACK[0]
REQD
SDS
DDS
CRTB_n
DMA Transfer
Figure 9.26 When the Destination Transfer Size Is Smaller (LVL = 0, HIEN = 1, REQD = 1, SDS > DDS in
CHCFG_n)
R01UH0437EJ0600 Rev.6.00
Jan 29, 2021
0
2
4
Read Read
3
1
4
Read Write
9. Direct Memory Access Controller
Read Read
3 3
1 1
4 4
Write Write
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Write
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1
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Write
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