Datasheet

RL78/L12 CHAPTER 16 DMA CONTROLLER
R01UH0330EJ0200 Rev.2.00 693
Dec 13, 2013
Figure 16-9. Example of Setting for UART Consecutive Reception + ACK Transmission
DEN0 = 1
DSA0 = 12H
DRA0 = FE00H
DBC0 = 0040H
DMC0 = 00H
DEN0 = 0
Note
Setting for UART reception
DST0 = 1
User program
processing
STG0 = 1
P10 = 1
P10 = 0
INTSR0 occurs.
INTDMA0
occurs.
DST0 = 0
RETI
Hardware operation
Start
End
RETI
INTSR0 interrupt routine
DMA0 transfer
DMA0 is started.
Note The DST0 flag is automatically cleared to 0 when a DMA transfer is completed.
Writing the DEN0 flag is enabled only when DST0 = 0. To terminate a DMA transfer without waiting for
occurrence of the interrupt of DMA0 (INTDMA0), set the DST0 bit to 0 and then the DEN0 bit to 0 (for details,
refer to 16.5.5 Forced termination by software).
Remark This is an example where a software trigger is used as a DMA start source.
If ACK is not transmitted and if only data is consecutively received from UART, the UART reception end
interrupt (INTSR0) can be used to start DMA for data reception.
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