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6.5.5. Peripheral Scatter-Gather Transfer
In memory scatter-gather transfer mode, the second and subsequent DMA transfers are performed
by auto-requests. On the other hand, in peripheral scatter-gather transfer mode, all DMA transfers
are performed by a DMA transfer request issued by a peripheral circuit or a software DMA request.
Transfer using primary data structure
(cycle_ctrl = 0x6, 2R = 4, N = 16)
DMA transfer request
Data transfer using the alternate data structure starts
immediately after data transfer using the primary data structure
has completed without arbitration.
DMA transfer request
DMA transfer request
DMA transfer request
Figure 6.5.5.1 Peripheral Scatter-Gather Transfer Operation Example
S1C31D50 TECHNICAL MANUAL
(Rev. 1.00)
Task A setting
Copy the data structure for
Task A to the alternate data structure..
Task B setting
Copy the data structure for
Task B to the alternate data structure.
DMA transfer request
DMA transfer request
DMA transfer request
Task C setting
Copy the data structure for
Task C to the alternate data structure
Task D setting
Copy the data structure for
Task D to the alternate data structure.
Seiko Epson Corporation
Transfer using alternate data structure
(cycle_ctrl = 0x7, 2R = 4, N = 3)
Task A
(cycle_ctrl = 0x7, 2R = 2, N = 8)
Task B
(cycle_ctrl = 0x7, 2R = 8, N = 5)
Task C
(cycle_ctrl = 0x1, 2R = 4, N = 4)
Task D
DMA transfer
completion interrupt
6-11
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