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MAP10 commands in INCR4 format are written to the
Data
register at offset 0x10 in
nanddata
, the same
as MAP10 commands in multitransaction format (described in
Multitransaction DMA Command
).
Table 10-8: MAP10 Burst DMA (INCR4) Command Structure
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Data Beat
<PP>
=number of pages
0x0: read. 0x1: write.
0x2
Beat 0
Memory address high
Beat 1
(25)
Memory address low
Beat 2
(25)
Burst length
INT
(26)
0x0
Beat 3
You can optionally send the 16-bit fields in the above table to the NAND flash controller as four separate
bursts of length 1 in sequential order. Altera recommends this method.
If you want the NAND flash controller DMA to perform cacheable accesses then you must configure the
cache bits by writing the
l3master
register in the
nandgrp
group in the system manager. The NAND
flash controller DMA must be idle before you use the system manager to modify its cache capabilities.
Related Information
•
on page 10-13
•
on page 10-10
•
on page 14-1
Command DMA
The flash controller supports command DMA, which provides descriptor-based command processing. Each
command descriptor performs one distinct operation on the flash controller. The host software can chain
these command descriptors sequentially as a linked-list of command descriptors and initiate command
DMA to operate on the descriptor chain. The DMA controller fetches a descriptor, carres out the operation
as described in the descriptor, writes the status of the operation completed, generates an interrupt if required,
and fetches the next descriptor. The host is not required to monitor the status of the issued commands,
because the DMA controller updates the status as part of the descriptor fields upon command completion.
The flash controller can support up to four command DMA channels simultaneously. When host software
starts all the command DMA channels in parallel, each channel processes one descriptor at a time from its
list of descriptors.
(25)
The buffer address in host memory, which must be aligned to 32 bits
(26)
INT specifies the host interrupt to be generated at the end of the complete DMA transfer. INT controls the
value of the
dma_cmd_comp
bit of the
intr_status0
register in the
status
group at the end of the
DMA transfer. INT can take on one of the following values:
0—Do not interrupt host. The
dma_cmd_comp
bit is set to 0.
1—Interrupt host. The
dma_cmd_com p
bit is set to 1.
NAND Flash Controller
Altera Corporation
cv_54010
Command DMA
10-16
2013.12.30