Datasheet

RL78/L12 CHAPTER 16 DMA CONTROLLER
R01UH0330EJ0200 Rev.2.00 678
Dec 13, 2013
CHAPTER 16 DMA CONTROLLER
The RL78/L12 has an internal DMA (Direct Memory Access) controller.
Data can be automatically transferred between the peripheral hardware supporting DMA, SFRs, and internal RAM
without via CPU.
As a result, the normal internal operation of the CPU and data transfer can be executed in parallel with transfer
between the SFR and internal RAM, and therefore, a large capacity of data can be processed. In addition, real-time
control using communication, timer, and A/D can also be realized.
16.1 Functions of DMA Controller
 Number of DMA channels: 2 channels
 Transfer unit: 8 or 16 bits
 Maximum transfer unit: 1024 times
 Transfer type: 2-cycle transfer (One transfer is processed in 2 clocks and the CPU stops during that
processing.)
 Transfer mode: Single-transfer mode
 Transfer request: Selectable from the following peripheral hardware interrupts
• A/D converter
• Serial interface
(CSI00, CSI01, UART0)
• Timer (channel 0, 1, 2, 3)
 Transfer target: Between SFR and internal RAM
Here are examples of functions using DMA.
• Successive transfer of serial interface
• Consecutive capturing of A/D conversion results
• Capturing A/D conversion result at fixed interval
• Capturing port value at fixed interval
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