Information

DMA_TCDn_SOFF field descriptions
Field Description
15–0
SOFF
Source address signed offset
Sign-extended offset applied to the current source address to form the next-state value as each source
read is completed.
21.3.19 TCD Transfer Attributes (DMA_TCD_ATTR)
Addresses: TCD0_ATTR is 4000_8000h base + 1006h offset = 4000_9006h
TCD1_ATTR is 4000_8000h base + 1026h offset = 4000_9026h
TCD2_ATTR is 4000_8000h base + 1046h offset = 4000_9046h
TCD3_ATTR is 4000_8000h base + 1066h offset = 4000_9066h
Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Read
SMOD SSIZE DMOD DSIZE
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_ATTR field descriptions
Field Description
15–11
SMOD
Source Address Modulo.
0 Source address modulo feature is disabled
≠0 This value defines a specific address range specified to be the value after SADDR + SOFF
calculation is performed or the original register value. The setting of this field provides the ability to
implement a circular data queue easily. For data queues requiring power-of-2 size bytes, the queue
should start at a 0-modulo-size address and the SMOD field should be set to the appropriate value
for the queue, freezing the desired number of upper address bits. The value programmed into this
field specifies the number of lower address bits allowed to change. For a circular queue application,
the SOFF is typically set to the transfer size to implement post-increment addressing with the SMOD
function constraining the addresses to a 0-modulo-size range.
10–8
SSIZE
Source data transfer size
The attempted use of a Reserved encoding causes a configuration error.
000 8-bit
001 16-bit
010 32-bit
011 Reserved
100 16-byte
101 32-byte
110 Reserved
111 Reserved
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. 361