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ML674001 Series/ML675001 Series User’s Manual
Chapter 22
Built-In Flash Memory
22-9
22.4.2
Command Entries
For command entries, use the JEDEC-conformed SDP command sequence.
After the SDP command sequence
is finished, the selected operation is initiated automatically.
If an incorrect address or data is entered in the SDP
command sequence, the SDP command sequence is suspended and the mode returns to read mode.
22.4.3
Read/Reset (Software Reset)
The Read/Reset command is used to end Software ID Entry/Verify Protect, or stop an erase or program
operation.
A Read/Reset operation is performed by entering an SDP command of either one cycle or three cycles to the
command register, and the mode returns to the read mode.
The flash memory is automatically set in read mode when the power is turned on.
22.4.4
Erase
An erase operation is executed by entering an SDP command of six cycles - the sector erase command, block
erase command, or chip erase command - to the command register, and is ended automatically by the control of
the internal timer within the flash memory.
During an erase operation, DATA_N poling that performs the detection of internal operations, the toggle bit,
hardware reset, and software reset become valid.
The Sector Erase command places the selected 2KB memory array in the state of “1.”
The Block Erase command places the selected 64KB memory array in the state of “1.”
The Chip Erase command places the entire memory array area in the state of “1.”
22.4.5
Program
A program operation is performed by entering an SDP command of four cycles - the Program command - to the
command register, and is ended automatically by the control of internal timing.
During a program operation, DATA_N poling that performs the detection of internal operations, the toggle bit,
hardware reset, and software reset become valid.
Please note, however, that the memory arrays of addresses to be programmed must be placed in the erase state
prior to programming.
Programming is performed in units of 16 bits (2 bytes).
Caution:
It is prohibited to re-program an address that has already been programmed once without erasing the
existing program first.
22.4.6
Protect
The protect operation disables erase and program operations in the specified areas.
There are two types of protect: block protect and chip protect.
Each type of protect is activated by entering an
SDP command of four cycles - the Block Protect or Chip Protect command - to the command register.
Block protect function protects an address space of 16KB (8 sectors) from the top address side, and chip protect
function protects the address space of the entire chip area.
Neither protect is canceled even if the power is turned off.
22.4.7
Protect Cancel
Protect is cancelled by entering an SDP command of four cycles - the Cancel Protect command - to the
command register.
The execution of the Cancel Protect command cancels both block protect and chip protect at the same time.