S3C2416X RISC MICROPROCESSOR
DMA CONTROLLER
8-5
Demand/Handshake Mode Comparison
−
Related to the Protocol between XnXDREQ and XnXDACK
These are two different modes related to the protocol between XnXDREQ and XnXDACK. Figure 8-2 shows the
differences between these two modes i.e., Demand and Handshake modes.
At the end of one transfer (Single/Burst transfer), DMA checks the state of double-synched XnXDREQ.
3.1.2 Demand
mode
•
If XnXDREQ remains asserted, the next transfer starts immediately. Otherwise it waits for XnXDREQ to be
asserted.
3.1.3 Handshake
mode
•
If XnXDREQ is deasserted, DMA deasserts XnXDACK in 2cycles. Otherwise it waits until XnXDREQ is
deasserted.
Caution: XnXDREQ has to be asserted (low) only after the deassertion (high) of XnXDACK.
Demand Mode
XSCLK
XnXDACK
XnXDACK
XnXDREQ
XnXDREQ
2cycles
Double
synch
Handshake Mode
BUS Acquisiton
1st Transfer
2nd Transfer
2cycles
Double
synch
2cycles
Actual Transfer
Read Write
Read Write
Read Write
Figure 8-2. Demand/Handshake Mode Comparison
Summary of Contents for S3C2416
Page 122: ...BUS MATRIX EBI S3C2416X RISC MICROPROCESSOR 3 4 NOTES ...
Page 204: ...DMA CONTROLLER S3C2416X RISC MICROPROCESSOR 8 18 NOTES ...
Page 284: ...WATCHDOG TIMER S3C2416X RISC MICROPROCESSOR 11 6 NOTES ...
Page 320: ...REAL TIME CLOCK S3C2416X RISC MICROPROCESSOR 13 16 NOTES ...
Page 344: ...UART S3C2416X RISC MICROPROCESSOR 14 24 NOTES ...
Page 380: ...USB2 0 DEVICE S3C2416X RISC MICROPROCESSOR 16 34 NOTES ...
Page 432: ...2D S3C2416X RISC MICROPROCESSOR 18 38 NOTES ...
Page 446: ...HS_SPI CONTROLLER S3C2416X RISC MICROPROCESSOR 19 14 NOTES ...
Page 604: ...S3C2416X RISC MICROPROCESSOR S3C2416X RISC MICROPROCESSOR 23 22 NOTES ...
Page 638: ...PCM AUDIO INTERFACE S3C2416X RISC MICROPROCESSOR 25 18 NOTES ...
Page 670: ...ELECTRICAL DATA S3C2416X RISC MICROPROCESSOR 26 32 NOTES ...