Information

21.3.26 TCD Current Minor Loop Link, Major Loop Count (Channel
Linking Enabled) (DMA_TCD_CITER_ELINKYES)
If TCDn_CITER[ELINK] is set, the TCDn_CITER register is defined as follows.
Addresses: TCD0_CITER_ELINKYES is 4000_8000h base + 1016h offset = 4000_9016h
TCD1_CITER_ELINKYES is 4000_8000h base + 1036h offset = 4000_9036h
TCD2_CITER_ELINKYES is 4000_8000h base + 1056h offset = 4000_9056h
TCD3_CITER_ELINKYES is 4000_8000h base + 1076h offset = 4000_9076h
Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Read
ELINK
0
LINKCH CITER
Write
Reset
x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x*
* Notes:
x = Undefined at reset.•
DMA_TCDn_CITER_ELINKYES field descriptions
Field Description
15
ELINK
Enable channel-to-channel linking on minor-loop complete
As the channel completes the minor loop, this flag enables linking to another channel, defined by the
LINKCH field. The link target channel initiates a channel service request via an internal mechanism that
sets the TCDn_CSR[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 MAJORELINK channel
linking.
NOTE: This bit must be equal to the BITER[ELINK] bit. Otherwise, a configuration error is reported.
0 The channel-to-channel linking is disabled
1 The channel-to-channel linking is enabled
14–11
Reserved
This read-only field is reserved and always has the value zero.
10–9
LINKCH
Link Channel Number
If channel-to-channel linking is enabled (ELINK = 1), then after the minor loop is exhausted, the eDMA
engine initiates a channel service request to the channel defined by these four bits by setting that
channel’s TCDn_CSR[START] bit.
8–0
CITER
Current Major Iteration Count
This 9-bit (ELINK = 1) or 15-bit (ELINK = 0) 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 (e.g.,
Table continues on the next page...
Chapter 21 Direct Memory Access Controller (eDMA)
K20 Sub-Family Reference Manual, Rev. 2, Feb 2012
Freescale Semiconductor, Inc. 367