Direct Memory Access Controller (DMAC)
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147
This field does not exist if the configuration parameter
DMAH_CH
x
_STAT_DST is set to False; in this case, the read-back value is
always 0.
36:34
PROTCTL
R/W
0x1
Protection Control bits used to drive the AHB HPROT[3:1] bus.
The
AMBA Specification
recommends that the default value of HPROT
indicates a non-cached, non-buffered, privileged data access. The reset
value is used to indicate such an access.
HPROT[0] is tied high because all transfers are data accesses, as there are
no opcode fetches.
There is a one-to-one mapping of these register bits to the HPROT[3:1]
master interface signals. Table 9-18 shows the mapping of bits in this field
to the AHB HPROT[3:1] bus.
33
FIFO_MODE
R/W
0x0
FIFO Mode Select. Determines how much space or data needs to be
available in the FIFO before a burst transaction request is serviced.
0 = Space/data available for single AHB transfer of the specified transfer
width.
1 = Data available is greater than or equal to half the FIFO depth for
destination transfers and space available is greater than half the fifo depth
for source transfers. The exceptions are at the end of a burst transaction
request or at the end of a block transfer.
32
FCMODE
R/W
0x0
Flow Control Mode. Determines when source transaction requests are
serviced when the Destination Peripheral is the flow controller.
0 = Source transaction requests are serviced when they occur. Data pre-
fetching is enabled.
1 = Source transaction requests are not serviced until a destination
transaction request occurs. In this mode, the amount of data transferred
from the source is limited so that it is guaranteed to be transferred to the
destination prior to block termination by the destination. Data pre-fetching
is disabled.
31
RELOAD_DST
N/A
0x0
Automatic Destination Reload. The DARx register can be automatically
reloaded from its initial value at the end of every block for multi-block
transfers. A new block transfer is then initiated.
This register does not exist if the configuration parameter
DMAH_CH
x
_MULTI_BLK_EN is not selected; in this case, the read-back
value is always 0.
30
RELOAD_SRC
R/W
0x0
Automatic Source Reload. The SARx register can be automatically reloaded
from its initial value at the end of every block for multi-block transfers. A
new block transfer is then initiated.
This field does not exist if the configuration parameter
DMAH_CH
x
_MULTI_BLK_EN is not selected; in this case, the read-back
value is always 0.
29:20
MAX_ABRST
R/W
0x0
Maximum AMBA Burst Length. Maximum AMBA burst length that is used
for DMA transfers on this channel. A value of 0 indicates that software is
not limiting the maximum AMBA burst length for DMA transfers on this
channel. This field does not exist if the configuration parameter
DMAH_MABRST is not selected; in this case, the read-back value is always
0, and the maximum AMBA burst length cannot be limited by software.
19
SRC_HS_POL
R/W
0x0
Source Handshaking Interface Polarity.
0 = Active high
1 = Active low
18
DST_HS_POL
R/W
0x0
Destination Handshaking Interface Polarity.
0 = Active high
1 = Active low
17
LOCK_B
R/W
0x0
Bus Lock Bit. When active, the AHB bus master signal hlock is asserted for
the duration specified in CFG
x
.LOCK_B_L.
This field does not exist if the configuration parameter
DMAH_CH
x
_LOCK_EN is set to False; in this case, the read-back value is
always 0.
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2019-05-15 10:08:03