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Control Registers and RAM
92
7.29
MibSPI DMA Channel Control Register (DMAxCTRL)
The number of bidirectional DMA channels (requires two physical DMA
channels at the DMA controller: one for the transmit path and one for the
receive path) is scalable by design. Depending on the implementation the
number of DMA channels and hence the number of DMA channel control
registers may vary. Each DMA channel can be configured via one dedicated
control register. The register description below shows one exemplary control
register which is identical for all DMA channels. For example, the control
register for DMA channel 0 is named "DMA0CTRL". The MibSPI supports up
to 8 bi-directional DMA channels.
Bits 31
ONESHOT.
Auto-disable of DMA channel after 1 transfers.
1 =
ONESHOT allows a block transfer of defined length (1)
mainly controlled by the MibSPI and not by the DMA controller. After
1 transfers the enable bits RXDMAENA and TXDMAENA are
automatically cleared by the MibSPI, hence no more DMA requests are
generated. In conjunction with NOBRK a burst transfer can be initiated
without any other transfer through another buffer.
0 =
The length of the block transfer is fully controlled by the DMA control-
ler. The enable bits RXDMAENA and TXDMAENA are not modified by
the MibSPI.
Bits 30:24
BUFID.
Buffer utilized for DMA transfer.
BUFID defines the buffer that is utilized for the DMA transfer. In order to
synchronize the transfer with the DMA controller with the NOBRK condition
the “suspend to wait until...” modes must be used (for more details refer to
Section 7.30.1).
Bits
31
30
24
23
20
19
16
0B8h+
4*X
ONE
SHOT
BUFID
RXDMACH
TXDMACH
X=0...7
RW-0
RW-0
RW-0
RW-0
Bits
15
14
13
12
8
RXDMAENA TXDMAENA
NOBRK
ICOUNT
X=0...7
RW-0
RW-0
RW-0
RW-0
Bits
7
6
5
0
Reserved
COUNT
X=0...7
U
R-0
Legend: R = Read, W = Write, C = Clear, U = Undefined,
-n
= Value after reset, x = indeterminate
Summary of Contents for TMS470R1x
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