K60P100M100SF2RM Datasheet, PDF (497/1809 Pages) Freescale Semiconductor, Inc – K60 Sub-Family Reference Manual

Chapter 21 Direct Memory Access Controller (eDMA)
For example, the following TCD entry is configured to transfer 16 bytes of data. The
eDMA is programmed for one iteration of the major loop transferring 16 bytes per
iteration. The source memory has a byte wide memory port located at 0x1000. The
destination memory has a 32-bit port located at 0x2000. The address offsets are
programmed in increments to match the transfer size: one byte for the source and four
bytes for the destination. The final source and destination addresses are adjusted to return
to their beginning values.
TCDn_CITER = TCDn_BITER = 1
TCDn_NBYTES = 16
TCDn_SADDR = 0x1000
TCDn_SOFF = 1
TCDn_ATTR[SSIZE] = 0
TCDn_SLAST = -16
TCDn_DADDR = 0x2000
TCDn_DOFF = 4
TCDn_ATTR[DSIZE] = 2
TCDn_DLAST_SGA= –16
TCDn_CSR[INT_MAJ] = 1
TCDn_CSR[START] = 1 (Should be written last after all other fields have been initialized)
All other TCDn fields = 0
This generates the following event sequence:
1. User write to the TCDn_CSR[START] bit requests channel service.
2. The channel is selected by arbitration for servicing.
3. eDMA engine writes: TCDn_CSR[DONE] = 0, TCDn_CSR[START] = 0,
TCDn_CSR[ACTIVE] = 1.
4. eDMA engine reads: channel TCD data from local memory to internal register file.
5. The source-to-destination transfers are executed as follows:
a. Read byte from location 0x1000, read byte from location 0x1001, read byte from
0x1002, read byte from 0x1003.
b. Write 32-bits to location 0x2000 → first iteration of the minor loop.
c. Read byte from location 0x1004, read byte from location 0x1005, read byte from
0x1006, read byte from 0x1007.
d. Write 32-bits to location 0x2004 → second iteration of the minor loop.
e. Read byte from location 0x1008, read byte from location 0x1009, read byte from
0x100A, read byte from 0x100B.
f. Write 32-bits to location 0x2008 → third iteration of the minor loop.
g. Read byte from location 0x100C, read byte from location 0x100D, read byte
from 0x100E, read byte from 0x100F.
K60 Sub-Family Reference Manual, Rev. 6, Nov 2011
Freescale Semiconductor, Inc.
497