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MPC563XM Reference Manual, Rev. 1
Freescale Semiconductor
141
Preliminary—Subject to Change Without Notice
7.3.1.16
Transfer Control Descriptor (TCD)
Each channel requires a 32-byte transfer control descriptor for defining the desired data movement
operation. The TCD structure was previously discussed in detail in
The channel
descriptors are stored in the local memory in sequential order: channel 0, channel 1, ... channel [n-1]. The
definitions of the TCD are presented as eight 32-bit values.
is a 32-bit view of the basic TCD
structure.
Table 7-18. TCDn 32-bit Memory Structure
define word 0 of the TCDn structure, the saddr field.
Figure 7-17. TCDn Word 0 (TCDn.saddr) Field
GRPPRI[1:0]
Channel n Current Group Priority
Group priority assigned to this channel group when
fixed-priority arbitration is enabled. These two bits are
read only; writes are ignored.
CHPRI[3:0]
Channel n Arbitration Priority
Channel priority when fixed-priority arbitration is
enabled.
DMA Offset
TCDn Field
(32 x n) + 0x00
Source Address (saddr)
(32 x n) + 0x04
Transfer Attributes
(smod, ssize, dmod, dsize)
Signed Source Address Offset (soff)
(32 x n) + 0x08
Inner “Minor” Byte Count (nbytes)
(32 x n) + 0x0c
Last Source Address Adjustment (slast)
(32 x n) + 0x10
Destination Address (daddr)
(32 x n) + 0x14
Current “Major” Iteration Count (citer)
Signed Destination Address Offset (doff)
(32 x n) + 0x18
Last Destination Address Adjustment/Scatter Gather Address (dlast_sga)
(32 x n) + 0x1c
Beginning “Major” Iteration Count (biter)
Channel Control/Status
(bwc, major.linkch, done, active,
major.e_link, e_sg, d_req, int_half, int_maj,
start)
Register address: DMA_ (32 x n) + 0x00
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
R
saddr[31:16]
W
RESET:
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
R
saddr[15:0]
W
RESET:
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
= Unimplemented
Name
Description
Value