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CHAPTER 17 DMA CONTROLLER
17.4.1 Step Transfer (Single/Block Transfer)
The step transfer (single/block transfer) performs one DMA transfer per transfer
request. Edge or level can be selected for the DREQ input.
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Step transfer (single/block transfer)
In step transfer mode, the bus access right is transferred to the CPU for each DMA transfer.
The unit of transfer unit is determined based on the block size. As the block size increases, the
DMAC transfer rate increases, but the CPU throughput decreases.
Figure 17.4-2 "Sample timing of step transfer" shows a sample timing of step transfer the case a
CLK doubler, internal descriptors, and a block size of 1 is used.
Figure 17.4-2 Sample timing of step transfer
CLK
DREQ
DACK
Internal
D-Abus
external
Abus
Descriptor access
Transfer
destination
Transfer
destination
Transfer
destination
Transfer
destination
Interval during
which the CPU
can use the DATA
bus
Step transfer [use of CLK doubler, internal descriptors, and block size = 1]
Summary of Contents for MB91150 Series
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Page 3: ...FUJITSU LIMITED FR30 32 BIT MICROCONTROLLER MB91150 Series HARDWARE MANUAL ...
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Page 10: ...vi ...
Page 112: ...96 CHAPTER 3 MEMORY SPACE CPU AND CONTROL UNIT ...
Page 178: ...162 CHAPTER 5 I O PORTS ...
Page 214: ...198 CHAPTER 7 16 BIT RELOAD TIMER ...
Page 240: ...224 CHAPTER 8 PPG TIMER ...
Page 310: ...294 CHAPTER 13 8 10 BIT A D CONVERTER ...
Page 318: ...302 CHAPTER 14 8 BIT D A CONVERTER ...
Page 362: ...346 CHAPTER 15 UART ...
Page 420: ...404 CHAPTER 19 PERIPHERAL STOP CONTROL ...
Page 428: ...412 CHAPTER 20 CALENDAR MACROS ...
Page 503: ...487 INDEX INDEX The index follows on the next page This is listed in alphabetic order ...
Page 510: ...494 INDEX ...
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