Information

DMA Controller (DMAC)
MPC8308 PowerQUICC II Pro Processor Reference Manual, Rev. 1
12-22 Freescale Semiconductor
Table 12-22 describes the TCD word 6 fields.
Figure 12-22 shows the TCD word 7 field.
Table 12-23 describes the TCD word 6 fields.
Table 12-22. TCD Word 6 (TCD.dlast_sga) Field Descriptions
Bits Name Description
31–0 dlast_sga
[31–0]
Last destination address adjustment or the memory address for the next transfer control descriptor to be
loaded into this channel (scatter/gather).
If (TCD.e_sg = 0), then
Adjustment value added to the destination address at the completion of the outer major iteration count.
This value can be applied to ‘restore’ the destination address to the initial value, or adjust the address to
reference the next data structure.
else,
This address points to the beginning of a 0-modulo-32 region containing the next transfer control
descriptor to be loaded into this channel. This channel reload is performed as the major iteration count
completes. The scatter/gather address must be 0-modulo-32, else a configuration error is reported.
Offset DMA_Offset = 0x1000 + (32 x n) + 0x1C Access: Read/Write
31 30 25 24 16
R
biter.
e_link
biter[14–9] OR biter.linkch [5–0] biter[8–0]
W
Reset All zeros
151413 876543210
R
bwc[1–0] major.linkch[5–0] done active
major.
e_link
e_sg —
int_
half
int_
maj
start
W
Reset All zeros
Figure 12-22. TCD Word 7 (TCDn.{biter, control/status]) Fields
Table 12-23. TCD Word 7 (TCD.{biter, control/status}) Field Descriptions
Bits Name Description
31 biter.e_link Enable channel-to-channel linking on minor loop complete. This is the initial value copied into the
citer.e_link field when the major loop is completed. The citer.e_link field controls channel linking
during channel execution. This bit must be equal to the citer.e_link bit otherwise a configuration
error is reported.
0 The channel-to-channel linking is disabled.
1 The channel-to-channel linking is enabled.
30–25 biter[14–9] or
biter.linkch
[5–0]
Beginning major iteration count or beginning link channel number. This is the initial value copied
into the citer field or citer.linkch field when the major loop is completed. The citer fields control
the iteration count and linking during channel execution.
If (TCD.biter.e_link = 0) then No channel-to-channel linking (or chaining) is performed after
the inner minor loop is exhausted. TCD word 5, bits [30–25] are used to form a 15-bit biter field.
Otherwise, after the minor loop is exhausted, the DMA engine initiates a channel service request
at the channel defined by biter.linkch[5–0] by setting that channel’s TCD.start bit. The value
contained in biter.linkch[5–0] must not exceed the number of implemented channels.