DMA_TCDn_BITER_ELINKNO field descriptions (continued)
Field
Description
0
The channel-to-channel linking is disabled
1
The channel-to-channel linking is enabled
14–0
BITER
Starting Major Iteration Count
As the transfer control descriptor is first loaded by software, this 9-bit (ELINK = 1) or 15-bit (ELINK = 0)
field must be equal to the value in the CITER field. As the major iteration count is exhausted, the contents
of this field are reloaded into the CITER field.
NOTE: When the software loads the TCD, this field must be set equal to the corresponding CITER field;
otherwise, a configuration error is reported. As the major iteration count is exhausted, the
contents of this field is reloaded into the CITER field. If the channel is configured to execute a
single service request, the initial values of BITER and CITER should be 0x0001.
22.4 Functional description
The operation of the eDMA is described in the following subsections.
22.4.1 eDMA basic data flow
The basic flow of a data transfer can be partitioned into three segments.
As shown in the following diagram, the first segment involves the channel activation:
Functional description
K22F Sub-Family Reference Manual , Rev. 3, 7/2014
476
Freescale Semiconductor, Inc.
