RM0082
BS_DMA controller
Doc ID 018672 Rev 1
345/844
19.7.16 DMACSync
register
The DMACSync (synchronization) is a RW register which allows to enable/disable
synchronization logic for the DMA request signals, namely DMACBREQ[15:0],
DMACSREQ[15:0], DMACLBREQ[15:0] and DMACLSREQ[15:0]. The DMACSync bit
assignments are given in
.
Note:
Synchronization logic must be used when the peripheral generating the DMA request runs
on a different clock to the DMAC. For peripherals running on the same clock as DMA,
disabling the synchronization logic improves the DMA request response time.
19.7.17 DMACCnSrcAddr
register
The DMACCnSrcAddr (channel n source address) is a RW register which contains the
current source address (byte-aligned) of the data to be transferred over the n-th DMA
channel. The DMACCnSrcAddr bit assignments are given in
.
Note:
Source and destination addresses must be aligned to the source and destination widths.
Software programs the DMACCnSrcAddr register directly before the appropriate DMA
channel is enabled. Once the corresponding DMA channel is enabled, this register is
updated:
●
As the source address is incremented,
●
By following the linked list when a complete packet of data has been transferred.
Reading the register when the DMA channel is active does not provide useful information.
This is because by the time the software has processed the value read, the channel might
have progressed. It is intended to be read-only when the channel has stopped, and in such
case, it shows the source address of the last item read.
[01]
M1
1’h0
AHB master 1 endianness configuration.
This bit enables to alter the endianness of the AHB master
interface 1, according to the same encoding as M2 (see
above).
[00]
E
1’h0
DMAC enable.
Setting this bit, the DMAC is enabled. Clearing this bit, the
DMAC is disabled reducing power consumption.
Table 294.
DMACConfiguration register bit assignments (continued)
Bit
Name
Reset value Description
Table 295.
DMACSync register bit assignments
Bit
Name
Reset
value
Description
[31:16]
Reserved
-
Read: undefined. Write as zero.
[15:00]
DMACSync
16’h0000
DMA synchronization logic enable.
Each bit is associated to one out of 16 peripheral
DMA request lines. A cleared bit (as for default)
indicates that the synchronization logic for the
request signals is enabled. In contrast, setting the
bit the synchronization logic is disabled.