S3C2416X RISC MICROPROCESSOR
DMA CONTROLLER
8-3
3 DMA
OPERATION
The details of DMA operation can be explained using three-state FSM (finite state machine) as follows:
State-1.
As an initial state, it waits for the DMA request. If it comes, go to state-2. At this state, DMA ACK
and INT REQ are 0.
State-2.
In this state, DMA ACK becomes 1 and the counter (CURR_TC) is loaded from DCON[19:0]
register. Note that DMA ACK becomes 1 and remains 1 until it is cleared later.
State-3.
In this state, sub-FSM handling the atomic operation of DMA is initiated. The sub-FSM reads the
data from the source address and then writes it to destination address. In this operation, data size
and transfer size (single or burst) are considered. This operation is repeated until the counter
(CURR_TC) becomes 0 in the whole service mode, while performed only once in a single service
mode. The main FSM (this FSM) counts down the CURR_TC when the sub-FSM finishes each of
atomic operation. In addition, this main FSM asserts the INT REQ signal when CURR_TC
becomes 0 and the interrupt setting of DCON [29] register is set to 1. In addition, it clears DMA
ACK if one of the following conditions is met.
1) CURR_TC becomes 0 in the whole service mode
2) atomic operation finishes in the single service mode.
Note that in the single service mode, these three states of main FSM are performed and then stops, and wait for
another DMA REQ. And if DMA REQ comes in all three states are repeated. Therefore, DMA ACK is asserted
and then de-asserted for each atomic transfer. In contrast, in the whole service mode, main FSM waits at state-3
until CURR_TC becomes 0. Therefore, DMA ACK is asserted during all the transfers and then de-asserted when
TC reaches 0.
However, INT REQ is asserted only if CURR_TC becomes 0 regardless of the service mode (single service mode
or whole service mode).
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 ...