SC32442B RISC MICROPROCESSOR DMA
8-3
EXTERNAL DMA DREQ/DACK PROTOCOL
There are three types of external DMA request/acknowledge protocols (Single service Demand, Single service
Handshake and Whole service Handshake mode). Each type defines how the signals like DMA request and
acknowledge are related to these protocols.
Basic DMA Timing
The DMA service means performing paired Reads and Writes cycles during DMA operation, which can make one
DMA operation. Figure 8-1 shows the basic Timing in the DMA operation of the SC32442B.
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The setup time and the delay time of XnXDREQ and XnXDACK are the same in all the modes.
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If the completion of XnXDREQ meets its setup time, it is synchronized twice and then XnXDACK is
asserted.
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After assertion of XnXDACK, DMA requests the bus and if it gets the bus it performs its operations.
XnXDACK is de-asserted when DMA operation is completed.
XSCLK
9.3ns Setup
9.3ns Setup
6.8ns Delay
6.6ns Delay
Read
Write
Min. 2XSCLK
XnXDREQ
XnXDACK
Min. 3XSCLK
Figure 8-1. Basic DMA Timing Diagram
Содержание SC32442B54
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Страница 308: ...PWM TIMER SC32442B RISC MICROPROCESSOR 10 20 NOTES ...
Страница 330: ...UART SC32442B RISC MICROPROCESSOR 11 22 NOTES ...
Страница 417: ...SC32442B RISC MICROPROCESSOR LCD CONTROLLER 15 45 NOTES ...
Страница 427: ...ADC AND TOUCH SCREEN INTERFACE SC32442B RISC MICROPROCESSOR 16 10 NOTES ...
Страница 511: ...BUS PRIORITIES SC32442B RISC MICROPROCESSOR 24 2 NOTES ...
Страница 562: ...K5D2G13ACM D075 Revision 1 0 December 2006 7 MCP MEMORY 2Gb 256Mb x8 NAND Flash Memory A Die ...
Страница 599: ...K5D2G13ACM D075 Revision 1 0 December 2006 44 MCP MEMORY 512Mb 16Mb x32 Mobile SDRAM C Die ...