Information

21.3.18 TCD Signed Source Address Offset (DMA_TCD_SOFF)
Addresses: 4000_8000h base + 1004h offset + (32d × n), where n = 0d to 15d
Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Read
SOFF
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_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: 4000_8000h base + 1006h offset + (32d × n), where n = 0d to 15d
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.
Table continues on the next page...
Memory map/register definition
K20 Sub-Family Reference Manual, Rev. 6, Nov 2011
458 Freescale Semiconductor, Inc.