PXD10RM Datasheet, PDF (497/1332 Pages) Freescale Semiconductor, Inc – PXD10 Microcontroller

Register address: DMA_Offset + 0x100 + n
0
1
2
3
4
5
6
7
R
ECP
DPA
GRPPRI[0:1]
CHPRI[0:3]
W
RESET:
0
0
*
*
*
*
*
*
= Unimplemented,
*
= defaults to channel number (n) after reset
Figure 15-18. DMA Channel n Priority (DCHPRIn) Register
Name
ECP
DPA
GRPPRI[0:1]
CHPRI[0:3]
Table 15-18. DMA Channel n Priority (DCHPRIn) field descriptions
Description
Enable Channel Preemption
Disable Preempt Ability
Channel n Current Group Priority
Channel n Arbitration Priority
Value
0 Channel n cannot be suspended by a higher priority
channel’s service request.
1 Channel n can be temporarily suspended by the
service request of a higher priority channel.
0 Channel n can suspend a lower priority channel.
1 Channel n cannot suspend any channel, regardless
of channel priority.
Group priority assigned to this channel group when
fixed-priority arbitration is enabled. These two bits are
read only; writes are ignored.
Channel priority when fixed-priority arbitration is
enabled.
15.2.1.18 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 Section 15.1.2, Features.” 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. Table 15-19 is a 32-bit view of the basic TCD
structure.
DMA Offset
0x1000 + (32 x n) + 0x00
0x1000 + (32 x n) + 0x04
0x1000 + (32 x n) + 0x08
0x1000 + (32 x n) + 0x0c
0x1000 + (32 x n) + 0x10
0x1000 + (32 x n) + 0x14
0x1000 + (32 x n) + 0x18
Table 15-19. TCDn 32-bit memory structure
TCDn Field
Source Address (saddr)
Transfer Attributes
(smod, ssize, dmod, dsize)
Signed Source Address Offset (soff)
Signed Minor Loop Offset (smloe, dmloe, mloff)
Inner “Minor” Byte
Count (nbytes)
Last Source Address Adjustment (slast)
Destination Address (daddr)
Current “Major” Iteration Count (citer) Signed Destination Address Offset (doff)
Last Destination Address Adjustment/Scatter Gather Address (dlast_sga)
Freescale Semiconductor
PXD10 Microcontroller Reference Manual, Rev. 1
Preliminary—Subject to Change Without Notice
15-27