NXP Semiconductors Kinetis KE1xZ256, Reference Manual

Page: 197 / 1325

Table 13-3. Modes of operation (continued)
Mode Description
A service request initiates a transfer of a specific number of bytes (NBYTES) as specified in the
transfer control descriptor (TCD). The minor loop is the sequence of read-write operations that
transfers these NBYTES per service request. Each service request executes one iteration of the
major loop, which transfers NBYTES of data.
Debug DMA operation is configurable in Debug mode via the control register:
• If CR[EDBG] is cleared, the DMA continues to operate.
• If CR[EDBG] is set, the eDMA stops transferring data. If Debug mode is entered while a
channel is active, the eDMA continues operation until the channel retires.
Wait Before entering Wait mode, the DMA attempts to complete its current transfer. After the transfer
completes, the device enters Wait mode.
13.3 Memory map/register definition
The eDMA's programming model is partitioned into two regions:
• The first region defines a number of registers providing control functions
• The second region corresponds to the local transfer control descriptor (TCD)
memory
13.3.1 TCD memory
Each channel requires a 32-byte transfer control descriptor for defining the desired data
movement operation. The channel descriptors are stored in the local memory in
sequential order: channel 0, channel 1, ... channel 7. Each TCDn definition is presented as
11 registers of 16 or 32 bits.
13.3.2 TCD initialization
Prior to activating a channel, you must initialize its TCD with the appropriate transfer
profile.
Chapter 13 Enhanced Direct Memory Access (eDMA)
Kinetis KE1xZ256 Sub-Family Reference Manual, Rev. 3, 07/2018
NXP Semiconductors 197