Altera cyclone V Technical Reference page 850

cv_5v4
2016.10.28
Note: For a read-modify-write command to work with hardware ECC, the entire page must be read into
system memory, modified, then written back to flash without relying on the RMW feature.
Read-Modify-Write Operation Flow
1. Start the flow by reading a page from the memory:
• Write to the command register, setting the
address of the desired block.
• Write 0x60 to the
This step makes the page available to you in the page buffer in the flash device.
2. Provide the destination page address:
• Write to the command register, setting the
tion address of the desired block.
• Write 0x61 to the
This step initiates the page program and provides the destination address to the device.
3. Use the MAP00 page buffer read and write commands to modify the data in the page buffer.
4. Write the page buffer data back to memory:
• Write to the command register, setting the
destination address.
• Write 0x62 to the
This step performs the write.
After the device completes the load operation, the NAND flash controller issues a
program_comp
program operation.
If the page program operation (as a part of an RMW operation) results in a program failure in the device,
program_fail
err_block_addr0
Copy-Back Operations
The NAND flash controller supports copy back operations. However, the flash device might have limited
support for this function. If you attempt to perform a copy-back operation on a device that does not
support copy-back, the NAND flash controller triggers an interrupt. An interrupt is also triggered if the
source block is not specified before the destination block is specified, or if the destination block is not
specified in the next command following a source block specification.
The NAND flash controller cannot do ECC validation in case of copy-back commands. The flash
controller copies the ECC data, but does not check it during the copy operation.
Note: Altera recommends that you use copy-back only if the ECC implemented in the flash controller is
strong enough so that the next access can correct accumulated errors.
The 8-bit value <PP> specifies the number of pages for copy-back. With this feature, the NAND flash
controller can copy multiple consecutive pages with a single command. When you issue a copy-back
command, the flash controller performs the operation in the background. The flash controller puts other
commands on hold until the current copy-back completes.
NAND Flash Controller
Send Feedback
register.
Data
register.
Data
register.
Data
interrupt is issued when the host issues the write command and the device completes the
interrupt is issued. The failing page's block and page address is updated in the
and
err_page_addr0
Read-Modify-Write Operation Flow
field to 2 and the
CMD_MAP
field to 2 and the
CMD_MAP
field to 2 and the
CMD_MAP
registers in the group.
status
13-29
field to the starting
BLK_ADDR
field to the destina‐
BLK_ADDR
field to the same
BLK_ADDR
interrupt. A
load_comp
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