
OneNAND256
FLASH MEMORY
37
8. Device Operation
The device supports both a limited command based and a register based interface for performing operations on the device, reading 
device ID, writing data to buffer etc.  The command based interface is active in the boot partition, i.e. commands can only be written 
with a boot area address.  Boot area data is only returned if no command has been issued prior to the read.
8.1 Command based operation
The entire address range, except for the boot area, can be used for the data buffer.  All commands are written to the boot partition.  Writes outside the 
boot partition are treated as normal writes to the buffers or registers.  The command consists of one or more cycles depending on the command.  After 
completion of the command the device starts its execution. Writing incorrect information which include address and data or writing an improper command 
will terminate the previous command sequence and make the device go to the ready status. The defined valid command sequences are stated in Table4.
Table 4. Command Sequences
NOTE:
1) DP(Data Partition) : DataRAM Area
2) BP(Boot Partition) : BootRAM Area [0000h ~ 01FFh, 8000h ~ 800Fh].
3) Load Data into Buffer operation is available within a block(64KB)
4) Load  1KB unit into DataRAM0.  Current Start address(FPA) is automatically incremented by 1KB unit after the load.  
5) 0000h -> Data is Manufacturer ID
   0001h -> Data is Device ID
   0002h -> Current Block Write Protection Status
6) WE toggling can terminate ’Read Identification Data’ operation.
8.1.1 Read Data from Buffer
     Buffer can be read by addressing a read to a wanted buffer area
8.1.2 Write Data to Buffer
     Buffer can be written by addressing a write to a wanted buffer area
8.1.3 Reset OneNAND
    Reset command is given by writing 00F0h to the boot partition address.  Reset will return all default values into the device.
8.1.4 Load Data into Buffer
   Load Data into Buffer command is a two-cycle command. Two sequential designated command activates this operation. Sequentially writing 00E0h 
and 0000h to the boot partition [0000h~01FFh, 8000h~800Fh] will load one page to DataRAM0. This operation refers to FBA and FPA. FSA, BSA, and 
BSC are not considered. 
   At the end of this operation, FPA will be automatically increased by 1. So continuous issue of this command will sequentially load data in next page to 
DataRAM0. This page address increment is restricted within a block.
   The default value of FBA and FPA is 0. Therefore, initial issue of this command after power on will load the first page of memory, which is usually boot 
code.
8.1.5 Read Identification Data
   Read Identification Data command consists of two cycles. It gives out the devices identification data according to the given address. The first cycle is 
0090h to the boot partition address and second cycle is read from the addresses specified in Table5.
Command Definition
Cycles
1st cycle
2nd cycle
Read Data from Buffer
Add
1
DP
1)
Data
Data
Write Data to Buffer
Add
1
DP
Data
Data
Reset OneNAND
Add
1
BP
2)
Data
00F0h
Load Data into Buffer
3)
Add
2
BP
BP
Data
00E0h
0000h
4)
Read Identification Data 
6)
Add
2
BP
XXXXh
5)
Data
0090h
Data