RM0082
BS_DMA controller
Doc ID 018672 Rev 1
351/844
19.7.22 DMACPeriphID
register
The DMACPeriphID are four 8 bit RO registers, which can be treated conceptually as a
single 32 bit register. These read-only registers provide the following peripheral options:
●
PartNumber[11:00] - This identifies the peripheral. The three digit product code 0x080
is used.
●
Designer ID[19:12] - This is the identification of the designer. ARM Limited is 0x41
(ASCII A).
●
Revision[23:20] - This is the revision number of the peripheral. The revision number
starts from 0.
●
Configuration[31:24] - This is the configuration option of the peripheral.
19.7.23 DMACPCellID
register
The DMACPCellID are four 8 bit RO registers, which can be treated conceptually as a single
32 bit register. The register is a standard cross-peripheral identification system. The
DMACPCellID register is set to 0xB105_F00D.
[04:01]
SrcPeriphe
ral
4’h0
Source peripheral.
This 4 bits field allows to select the DMA destination (resp.
source) request peripheral. The value is ignored in case the
destination (resp. source) of the transfer is the memory.
Note: The DestPeripheral and SrcPeripheral fields are the
binary value of the request line (4’h0 to 4’hF, that is 0 to 15)
and not a mask value.
[00]
E
1’h0
Channel enable.
Setting this bit, the relevant DMA channel is enabled. When
this bit is cleared, the current AHB transfer – if any – is firstly
completed (losing any data in the channel FIFO), then the
channel is disabled.
Note: Restarting the DMA channel by setting back the E bit
results in unpredictable effects and the channel must be fully
re-initialized.
If a DMA channel has to be disabled without losing data in its
channel’s FIFO, at first the Halt bit must be set, so that
subsequent DMA requests are ignored. Then, the Active bit
must be polled until it reaches 1‘b0, indicating that there is no
data left in the channel’s FIFO. Finally, the Channel Enable
bit can be cleared.
The DMA channel is also disabled (and the E bit cleared)
when either the last LLI is reached or if a channel error is
encountered.
Reading this bit indicates whether the DMA channel is
enabled or disabled.
Table 300.
DMAC Configuration register bit assignments (continued)
Bit
Name
Reset value Description