commands received so far, reset itself to the initial state, service the new command and issue an
unsup_cmd
interrupt.
Burst DMA Command
The burst DMA command carries the same information as multitransaction DMA command-data pairs,
but in a different format. When the MAP10 command is sent in a single transaction of four data beats (a
burst transfer of size 4), the flash controller interprets the least significant 16 bits of data in a beat and the
rest of the upper bits are ignored.
When a burst DMA command is received, the flash controller decodes the channel number, concatenates
descriptor address, and fetches the descriptor from memory.
MAP10 Burst DMA Command Structure
5:0
7:6
15:8
31:16
Data beat
Channel
number (0-3)
0x2
0x00
Reserved
Beat 0
Descriptor address [31:16]
Not used
Beat 1
Descriptor address[15:0]
Not used
Beat 2
Reserved
Beat 3
Descriptor Lists
While the flash controller processes a descriptor list, the host software can append descriptors to the descriptor
list and issue a command-DMA command with the address of the appended descriptor to the flash controller.
The flash controller processes the last descriptor and continues with the appended descriptors.
Whenever a DMA channel receives error indication, the status field of the descriptor is updated with the
error information. The affected channel stops any subsequent descriptors for the channel and sets the error
bit in the
cmd_dma_channel_error
register. The channel does not execute any sync buffer updated
associated with the descriptor. If the
cmd_dma_error_enable
bit is set, the flash controller does not
accept any further MAP10 command-DMA commands from the host until the host acknowledges the error
in
cmd_dma_channel_error
register. Other channels are not affected, and continue their normal
operations.
The host software can use channel reset commands to stop a channel from processing the next descriptor
in the descriptor chain. The selected channel does not process any new descriptors until the flash controller
receives a new MAP10 command-DMA command.
Related Information
on page 10-23
DMA Command Descriptor
The command descriptor consists of the pointer to the current command as well as pointer to the next
descriptor.
Altera Corporation
NAND Flash Controller
10-19
Burst DMA Command
cv_54010
2013.12.30