One-Time Programmable (OTP) Operations
This Micron NAND Flash device offers a protected, one-time programmable NAND Flash memory area. Each target has a an OTP area with a range of OTP pages (see Ta-ble 15 (page 102)); the entire range is guaranteed to be good. Customers can use the OTP area in any way they desire; typical uses include programming serial numbers or other data for permanent storage.
The OTP area leaves the factory in an erased state (all bits are 1). Programming an OTP page changes bits that are 1 to 0, but cannot change bits that are 0 to 1. The OTP area cannot be erased, even if it is not protected. Protecting the OTP area prevents further programming of the pages in the OTP area.
Enabling the OTP Operation Mode
The OTP area is accessible while the OTP operation mode is enabled. To enable OTP operation mode, issue the SET FEATURES (EFh) command to feature address 90h and write 01h to P1, followed by three cycles of 00h to P2 through P4.
When the target is in OTP operation mode, all subsequent PAGE READ (00h-30h) and PROGRAM PAGE (80h-10h) commands are applied to the OTP area.
ERASE commands are not valid while the target is in OTP operation mode.
Programming OTP Pages
Each page in the OTP area is programming using tthe PROGRAM OTP PAGE (80h-10h)command. Each page can be programmed more than once, in sections, up to the maxi-mum number allowed (see NOP in Table 15 (page 102)). The pages in the OTP area must be programmed in ascending order.
If the host issues a PAGE PROGRAM (80h-10h) command to an address beyond the max-imum page-address range, the target will be busy for t OBSY and the WP# status register bit will be 0, meaning that the page is write-protected.
Protecting the OTP Area
To protect the OTP area, issue the OTP PROTECT (80h-10h) command to the OTP Pro-tect Page. When the OTP area is protected it cannot be programmed further. It is not possible to unprotect the OTP area after it has been protected.
Reading OTP Pages
To read pages in the OTP area, whether the OTP area is protected or not, issue the PAGE READ (00h-30h) command.
If the host issues the PAGE READ (00h-30h) command to an address beyond the maxi-mum page-address range, the data output will not be valid. To determine whether the target is busy during an OTP operation, either monitor R/B# or use the READ STATUS (70h) command. Use of the READ STATUS ENHANCED (78h) command is prohibited while the OTP operation is in progress.
Returning to Normal Array Operation Mode
To exit OTP operation mode and return to normal array operation mode, issue the SET FEATURES (EFh) command to feature address 90h and write 00h to P1 through P4.If the RESET (FFh) command is issued while in OTP operation mode, the target will exit OTP operation mode and enter normal operating mode. If the synchronous interface is active, the target will exit OTP operation and enable the asynchronous interface.
16Gb, 32Gb, 64Gb, 128Gb Asynchronous/Synchronous NAND One-Time Programmable (OTP) Operations
Interleaved Die (Multi-LUN) Operations
In devices that have more than one die (LUN) per target, it is possible to improve per-formance by interleaving operations between the die (LUNs). An interleaved die (multi-LUN) operation is one that is issued to an idle die (LUN) (RDY = 1) while another die (LUN) is busy (RDY = 0).
Interleaved die (multi-LUN) operations are prohibited following RESET (FFh, FCh), iden-tification (90h, ECh, EDh), and configuration (EEh, EFh) operations until ARDY =1 for all of the die (LUNs) on the target.
During an interleaved die (multi-LUN) operation, there are two methods to determine operation completion. The R/B# signal indicates when all of the die (LUNs) have finish-ed their operations. R/B# remains LOW while any die (LUN) is busy. When R/B# goes HIGH, all of the die (LUNs) are idle and the operations are complete. Alternatively, the READ STATUS ENHANCED (78h) command can report the status of each die (LUN) in-dividually.
If a die (LUN) is performing a cache operation, like PROGRAM PAGE CACHE (80h-15h),then the die (LUN) is able to accept the data for another cache operation when status register bit 6 is 1. All operations, including cache operations, are complete on a die when status register bit 5 is 1.
Use the READ STATUS ENHANCED (78h) command to monitor status for the ad-dressed die (LUN).
When multi-plane commands are used with interleaved die (multi-LUN) operations, the multi-plane commands must also meet the requirements, see Multi-Plane Operations for details. After the READ STATUS ENHANCED (78h) command has been issued, the READ STATUS (70h) command may be issued for the previously ad-dressed die (LUN).
See Command Definitions for the list of commands that can be issued while other die (LUNs) are busy.
During an interleaved die (multi-LUN) operation that involves a PROGRAM-seriesignore subsequent bad blocks
(80h-10h, 80h-15h, 80h-11h) operation and a READ operation, the PROGRAM-series op-eration must be issued before the READ-series operation. The data from the READ-series operation must be output to the host before the next PROGRAM-series operation is issued. This is because the 80h command clears the cache register contents of all cache registers on all planes.
16Gb, 32Gb, 64Gb, 128Gb Asynchronous/Synchronous NAND Interleaved Die (Multi-LUN) Operations
Table 13: Parameter Page Data Structure  (Continued)
16Gb, 32Gb, 64Gb, 128Gb Asynchronous/Synchronous NAND Parameter Page Data Structure Tables

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