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Architecture
589
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
Enhanced Direct Memory Access (EDMA3) Controller
17.2.3.2 EDMA3 Channel Parameter Set Fields
17.2.3.2.1
Channel Options Parameter (OPT)
The 32-bit channel options parameter (OPT) specifies the transfer configuration options. The channel
options parameter (OPT) is described in
17.2.3.2.2 Channel Source Address (SRC)
The 32-bit source address parameter specifies the starting byte address of the source. For SAM in
increment mode, there are no alignment restrictions imposed by EDMA3. For SAM in constant addressing
mode, you must program the source address to be aligned to a 256-bit aligned address (5 LSBs of
address must be 0). The EDMA3TC will signal an error, if this rule is violated. See
for
additional details.
17.2.3.2.3 Channel Destination Address (DST)
The 32-bit destination address parameter specifies the starting byte address of the destination. For DAM
in increment mode, there are no alignment restrictions imposed by EDMA3. For DAM in constant
addressing mode, you must program the destination address to be aligned to a 256-bit aligned address
(5 LSBs of address must be 0). The EDMA3TC will signal an error, if this rule is violated. See
for additional details.
17.2.3.2.4 Count for 1st Dimension (ACNT)
ACNT represents the number of bytes within the 1st dimension of a transfer. ACNT is a 16-bit unsigned
value with valid values between 0 and 65 535. Therefore, the maximum number of bytes in an array is
65 535 bytes (64K – 1 bytes). ACNT must be greater than or equal to 1 for a TR to be submitted to
EDMA3TC. A transfer with ACNT equal to 0 is considered either a null or dummy transfer.
See
and
for details on dummy/null completion conditions.
17.2.3.2.5 Count for 2nd Dimension (BCNT)
BCNT is a 16-bit unsigned value that specifies the number of arrays of length ACNT. For normal
operation, valid values for BCNT are between 1 and 65 535. Therefore, the maximum number of arrays in
a frame is 65 535 (64K – 1 arrays). A transfer with BCNT equal to 0 is considered either a null or dummy
transfer.
See
and
for details on dummy/null completion conditions.
17.2.3.2.6 Count for 3rd Dimension (CCNT)
CCNT is a 16-bit unsigned value that specifies the number of frames in a block. Valid values for CCNT are
between 1 and 65 535. Therefore, the maximum number of frames in a block is 65 535 (64K – 1 frames).
A transfer with CCNT equal to 0 is considered either a null or dummy transfer.
See
and
for details on dummy/null completion conditions.
17.2.3.2.7 BCNT Reload (BCNTRLD)
BCNTRLD is a 16-bit unsigned value used to reload the BCNT field once the last array in the
2nd dimension is transferred. This field is only used for A-synchronized transfers. In this case, the
EDMA3CC decrements the BCNT value by 1 on each TR submission. When BCNT reaches 0, the
EDMA3CC decrements CCNT and uses the BCNTRLD value to reinitialize the BCNT value.
For AB-synchronized transfers, the EDMA3CC submits the BCNT in the TR and the EDMA3TC
decrements BCNT appropriately. For AB-synchronized transfers, BCNTRLD is not used.