Enhanced Direct Memory Access (eDMA)
MPC5606S Microcontroller Reference Manual, Rev. 7
498 Freescale Semiconductor
When minor loop mapping (DMACR[EMLM] = 1) is enabled, TCD word2 is redefined as four fields: a
source minor loop offset enable, a destination minor loop offset enable, a minor loop offset field and a
nbytes field.
Table 15-22. TCDn Word 2 (TCDn.nbytes) field description
Name Description
nbytes[0:31] Inner “minor” byte transfer count
Number of bytes to be transferred in each service request of the channel.
As a channel is activated, the contents of the appropriate TCD is loaded into the DMA engine,
and the appropriate reads and writes performed until the complete byte transfer count has been
transferred. This is an indivisible operation and cannot be stalled or halted. After the minor
count is exhausted, the current values of the saddr and daddr are written back into the local
memory, the major iteration count is decremented and restored to the local memory. If the
major iteration count is completed, additional processing is performed.
The nbytes value 0x0000_0000 is interpreted as 0x1_0000_0000, thus specifying a 4 GB
transfer.
Address: DMA_Offset + 0x1000 + (32 × n) + 0x08 Access: User read/write
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
R
smlo
e
dmlo
e
mloff[0:13] or nbytes[0:13]
W
Reset — — — — — — — — — — — — — — — —
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
R
mloff[14:19] or nbytes[14:19] nbytes[20:29]
W
Reset — — — — — — — — — — — — — — — —
Figure 15-28. TCDn Word 2 (TCDn.nbytes) field (DMACR[EMLM] = 1)
Table 15-23. TCDn Word 2 (TCDn.nbytes) field descriptions
Name Description
smloe Source minor loop offset enable
This flag selects whether the minor loop offset is applied to the source address upon minor
loop completion.
0 The minor loop offset is not applied to the saddr.
1 The minor loop offset is applied to the saddr.
dmloe Destination minor loop offset enable
This flag selects whether the minor loop offset is applied to the destination address upon
minor loop completion.
0 The minor loop offset is not applied to the daddr.
1 The minor loop offset is applied to the daddr.
To Next Page
Loading...
