Ameba-D User Manual
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The DMA transfer flow is shown in Fig 9-54
Fig 9-54 DMA transfer flow for source and destination address auto-reloaded
9.4.5.4
Multi-Block Transfer with Source Address Auto-Reloaded and Linked List Destination Address (Row 7)
Note
: This type of multi-block transfer can only be enabled when either of the following parameters is set:
DMAH_CHx_MULTI_BLK_TYPE = 0
DMAH_CHx_MULTI_BLK_TYPE = RELOAD_LLP
(1)
Read the Channel Enable register in order to choose a free (disabled) channel.
(2)
Set up the chain of Linked List Items (otherwise known as block descriptors) in memory. Write the control information in the LLI.CTLx
register location of the block descriptor for each LLI in memory (see Fig 9-45) for channel
x
. For example, in the register, you can program
the following:
a)
Set up the transfer type (memory or non-memory peripheral for source and destination) and flow control device by programming
the TT_FC of the CTLx register. Table 9-17 lists the decoding for this field.
b)
Set up the transfer characteristics, such as:
i.
Transfer width for the source in the SRC_TR_WIDTH field. Table 9-16
lists the decoding for this field.
ii.
Transfer width for the destination in the DST_TR_WIDTH field. Table 9-16
lists the decoding for this field.
iii.
Source master layer in the SMS field where the source resides.
iv.
Destination master layer in the DMS field where the destination resides.
v.
Incrementing/decrementing or fixed address for the source in the SINC field.
vi.
Incrementing/decrementing or fixed address for the destination in the DINC field.
(3)
Write the starting source address in the SARx register for channel
x
.
Note
: The values in the LLI.SARx register locations of each of the Linked List Items (LLIs) set up in memory, although fetched during an LLI
fetch, are not used.
(4)
Write the channel configuration information into the CFGx register for channel
x.
a)
Designate the handshaking interface type (hardware or software) for the source and destination peripherals; this is not required for
memory.
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2019-05-15 10:08:03