Functional Description
11.3.3.2.10 Source C Index (SRCCIDX)
SRCCIDX is a 16-bit signed value (2s complement) used for source address modification in the
3rd dimension. Valid values for SRCCIDX are between –32 768 and 32 767. It provides a byte address
offset from the beginning of the current array (pointed to by SRC address) to the beginning of the first
source array in the next frame. It applies to both A-synchronized and AB-synchronized transfers. Note that
when SRCCIDX is applied, the current array in an A-synchronized transfer is the last array in the frame
(
), while the current array in an AB-synchronized transfer is the first array in the frame
(
11.3.3.2.11 Destination C Index (DSTCIDX)
DSTCIDX is a 16-bit signed value (2s complement) used for destination address modification in the
3rd dimension. Valid values are between –32 768 and 32 767. It provides a byte address offset from the
beginning of the current array (pointed to by DST address) to the beginning of the first destination array
TR in the next frame. It applies to both A-synchronized and AB-synchronized transfers. Note that when
DSTCIDX is applied, the current array in an A-synchronized transfer is the last array in the frame
(
), while the current array in a AB-synchronized transfer is the first array in the frame
(
11.3.3.2.12 Link Address (LINK)
The EDMA3CC provides a mechanism, called linking, to reload the current PaRAM set upon its natural
termination (that is, after the count fields are decremented to 0) with a new PaRAM set. The 16-bit
parameter LINK specifies the byte address offset in the PaRAM from which the EDMA3CC loads/reloads
the next PaRAM set during linking.
You must program the link address to point to a valid aligned 32-byte PaRAM set. The 5 LSBs of the LINK
field should be cleared to 0.
The EDMA3CC ignores the upper 2 bits of the LINK entry, allowing the programmer the flexibility of
programming the link address as either an absolute/literal byte address or use the PaRAM-base-relative
offset address. Therefore, if you make use of the literal address with a range from 4000h to 7FFFh, it will
be treated as a PaRAM-base-relative value of 0000h to 3FFFh.
You should make sure to program the LINK field correctly, so that link update is requested from a PaRAM
address that falls in the range of the available PaRAM addresses on the device.
A LINK value of FFFFh is referred to as a NULL link that should cause the EDMA3CC to perform an
internal write of 0 to all entries of the current PaRAM set, except for the LINK field that is set to FFFFh.
Also, see
for details on terminating a transfer.
11.3.3.3 Null PaRAM Set
A null PaRAM set is defined as a PaRAM set where all count fields (ACNT, BCNT, and CCNT) are
cleared to 0. If a PaRAM set associated with a channel is a NULL set, then when serviced by the
EDMA3CC, the bit corresponding to the channel is set in the associated event missed register (EMR,
EMRH, or QEMR). This bit remains set in the associated secondary event register (SER, SERH, or
QSER). This implies that any future events on the same channel are ignored by the EDMA3CC and you
are required to clear the bit in SER, SERH, or QSER for the channel. This is considered an error
condition, since events are not expected on a channel that is configured as a null transfer. See
and
for more information on the SER and EMR registers,
respectively.
11.3.3.4 Dummy PaRAM Set
A dummy PaRAM set is defined as a PaRAM set where at least one of the count fields (ACNT, BCNT, or
CCNT) is cleared to 0 and at least one of the count fields is nonzero.
888
Enhanced Direct Memory Access (EDMA)
SPRUH73H – October 2011 – Revised April 2013
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