RC28F256 Intel Corporation, RC28F256 Datasheet - Page 67

• Manufacturer Part Number: RC28F256
• Description: Intel StrataFlash Embedded Memory
• Manufacturer: Intel Corporation

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12.0
12.1
12.2
Datasheet
Erase Operations
Flash erasing is performed on a block basis. An entire block is erased each time an erase command
sequence is issued, and only one block is erased at a time. When a block is erased, all bits within
that block read as logical ones. The following sections describe block erase operations in detail.
Block Erase
Block erase operations are initiated by writing the Block Erase Setup command to the address of
the block to be erased (see
Confirm command is written to the address of the block to be erased. If the device is placed in
standby (CE# deasserted) during an erase operation, the device completes the erase operation
before entering standby.V
“Block Erase Flowchart” on page
During a block erase, the Write State Machine (WSM) executes a sequence of internally-timed
events that conditions, erases, and verifies all bits within the block. Erasing the flash memory array
changes “zeros” to “ones”. Memory array bits that are ones can be changed to zeros only by
programming the block (see
The Status Register can be examined for block erase progress and errors by reading any address.
The device remains in the Read Status Register state until another command is written. SR[0]
indicates whether the addressed block is erasing. Status Register bit SR[7] is set upon erase
completion.
Status Register bit SR[7] indicates block erase status while the sequence executes. When the erase
operation has finished, Status Register bit SR[5] indicates an erase failure if set. SR[3] set would
indicate that the WSM could not perform the erase operation because V
acceptable limits. SR[1] set indicates that the erase operation attempted to erase a locked block,
causing the operation to abort.
Before issuing a new command, the Status Register contents should be examined and then cleared
using the Clear Status Register command. Any valid command can follow once the block erase
operation has completed.
Erase Suspend
Issuing the Erase Suspend command while erasing suspends the block erase operation. This allows
data to be accessed from memory locations other than the one being erased. The Erase Suspend
command can be issued to any device address. A block erase operation can be suspended to
perform a word or buffer program operation, or a read operation within any block except the block
that is erase suspended (see
When a block erase operation is executing, issuing the Erase Suspend command requests the WSM
to suspend the erase algorithm at predetermined points. The device continues to output Status
Register data after the Erase Suspend command is issued. Block erase is suspended when Status
Register bits SR[7,6] are set. Suspend latency is specified in
Characteristics” on page
Intel StrataFlash
Order Number: 306666, Revision: 001
45.
PP
Section 9.2, “Device Commands” on page
Figure 41, “Program Suspend/Resume Flowchart” on page
must be above V
Section 11.0, “Programming Operations” on page
89).
®
Embedded Memory (P30)
PPLK
and the block must be unlocked (see
Section 7.5, “Program and Erase
50). Next, the Block Erase
PP
was outside of its
1-Gbit P30 Family
61).
86).
April 2005
Figure 44,
67