Figure 62: PROGRAM/ERASE Issued to Locked Block
R/B#
I/Ox
t Locked block READ STATUS BLOCK LOCK READ STATUS (7Ah)
The BLOCK LOCK READ STATUS (7Ah) command is used to determine the protection
status of individual blocks. The address cycles have the same format, as shown below,
and the invert area bit should be set LOW. On the falling edge of RE# the I/O pins output
the block lock status register, which contains the information on the protection status
of the block.
Table 20: Block Lock Status Register Bit Definitions
ignore subsequent bad blocksFigure 63: BLOCK LOCK READ STATUS
BLOCK LOCK
READ STATUS Block address
CLE
CE#
WE#ALE
RE#
I/Ox 4Gb, 8Gb, 16Gb: x8, x16 NAND Flash Memory Block Lock Feature
Figure 64: BLOCK LOCK Flowchart
4Gb, 8Gb, 16Gb: x8, x16 NAND Flash Memory Block Lock Feature
One-Time Programmable (OTP) Operations
This Micron NAND Flash device offers a protected, one-time programmable NAND Flash memory area. Thirty full pages (2112 bytes per page) of OTP data are available on the device, and the entire range is guaranteed to be good. The OTP area is accessible only through the OTP commands. Customers can use the OTP area any way they
choose; typical uses include programming serial numbers or other data for permanent storage.
The OTP area leaves the factory in an unwritten state (all bits are 1s). Programming or partial-page programming enables the user to program only 0 bits in the OTP area. The OTP area cannot be erased, whether it is protected or not. Protecting the OTP area pre-vents further programming of that area.
Micron provides a unique way to program and verify data before permanently protect-ing it and preventing future changes. The OTP area is only accessible while in OTP oper-ation mode. To set the device to OTP operation mode, issue the SET FEATURE (EFh)command to feature address 90h
and write 01h to P1, followed by three cycles of 00h to P2-P4. For parameters to enter OTP mode, see Features Operations.
When the device is in OTP operation mode, all subsequent PAGE READ (00h-30h) and PROGRAM PAGE (80h-10h) commands are applied to the OTP area. The OTP area is as-signed to page addresses 02h-1Fh. To program an OTP page, issue the PROGRAM PAGE (80h-10h) command. The pages must be programmed in the ascending order. Similarly,to read an OTP page, issue the PAGE READ (00h-30h) command.
Protecting the OTP is done by entering OTP protect mode. To set the device to OTP pro-tect mode, issue the SET FEATURE (EFh) command to feature address 90h and write 03h to P1, followed by three cycles of 00h to P2-P4.
To determine whether the device is busy during an OTP operation, either monitor R/B#or use the READ STATUS (70h) command.
To exit OTP operation or protect mode, write 00h to P1 at feature address 90h.
Legacy OTP Commands
For legacy OTP commands, OTP DATA PROGRAM (A0h-10h), OTP DATA PROTECT (A5h-10h), and OTP DATA READ (AFh-30h), refer to the MT29F4GxxAxC data sheet.
4Gb, 8Gb, 16Gb: x8, x16 NAND Flash Memory One-Time Programmable (OTP) Operations

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