NXP Semiconductors MPC5605BK, Reference Manual

Page: 275 / 964

Chapter 16 Enhanced Direct Memory Access (eDMA)
MPC5606BK Microcontroller Reference Manual, Rev. 2
Freescale Semiconductor 275
160 /
0x14 [0]
CITER.E_LINK Enable channel-to-channel linking on minor loop completion. As the
channel completes the inner minor loop, this flag enables the linking to
another channel, defined by CITER.LINKCH[0:5]. The link target channel
initiates a channel service request via an internal mechanism that sets the
TCD.START bit of the specified channel. If channel linking is disabled, the
CITER value is extended to 15 bits in place of a link channel number. If the
major loop is exhausted, this link mechanism is suppressed in favor of the
MAJOR.E_LINK channel linking.
0 The channel-to-channel linking is disabled.
1 The channel-to-channel linking is enabled.
Note: This bit must be equal to the BITER.E_LINK bit otherwise a
configuration error will be reported.
161–166 /
0x14 [1:6] CITER
[0:5]
or
CITER.LINKCH
[0:5]
Current major iteration count or link channel number.
If channel-to-channel linking is disabled (TCD.CITER.E_LINK = 0), then
• No channel-to-channel linking (or chaining) is performed after the inner
minor loop is exhausted. TCD bits [161:175] are used to form a 15-bit
CITER field.
Otherwise,
• After the minor loop is exhausted, the DMA engine initiates a channel
service request at the channel defined by CITER.LINKCH[0:5] by setting
that channel’s TCD.START bit.
167–175 /
0x14 [7:15]
CITER
[6:14]
Current major iteration count. This 9- or 15-bit count represents the current
major loop count for the channel. It is decremented each time the minor
loop is completed and updated in the transfer control descriptor memory.
After the major iteration count is exhausted, the channel performs a number
of operations (for example, final source and destination address
calculations), optionally generating an interrupt to signal channel
completion before reloading the CITER field from the beginning iteration
count (BITER) field.
Note: When the CITER field is initially loaded by software, it must be set
to the same value as that contained in the BITER field.
Note: If the channel is configured to execute a single service request, the
initial values of BITER and CITER should be 0x0001.
176–191 /
0x14 [16:31]
DOFF
[0:15]
Destination address signed Offset. Sign-extended offset applied to the
current destination address to form the next-state value as each destination
write is completed.
Table 16-19. TCD n field descriptions (continued)
Bits /
Word Offset
[n:n]
Name Description