TC1796
System Units (Vol. 1 of 2)
Direct Memory Access Controller
User’s Manual
12-90
V2.0, 2007-07
DMA, V2.0
The Shadow Address Register holds the shadowed source or destination address before
it is written into the source or destination address register. SHADRmx can be read only.
SHADRmx is written when source or destination address buffering is selected
(ADRCRmx.SHCT = 01
B
or ADRCRmx.SHCT = 10
B
) and a transaction is running. While
the shadow mechanism is disabled, SHADR is set to 0000 0000
H
.
The value stored in the SHADR is automatically set to 0000 0000
H
when the shadow
transfer takes place. The user can read the shadow register in order to detect if the
shadow transfer has already taken place. If the value in SHADR is 0000 0000
H
, no
shadow transfer can take place and the corresponding address register is modified
according to the circular buffer rules.
DMA_SHADR0x (x = 0-7)
DMA Channel 0x Shadow Address Register
(x*20
H
+98
H
)
Reset Value: 0000 0000
H
DMA_SHADR1x (x = 0-7)
DMA Channel 1x Shadow Address Register
(x*20
H
+198
H
)
Reset Value: 0000 0000
H
31
0
SHADR
rh
Field
Bits
Type Description
SHADR
[31:0]
rh
Shadowed Address
This bit field holds the shadowed 32-bit source or
destination address of DMA channel mx.