Bus Operations
CE# LOW and RST# HIGH enable READ operations. The device internally decodes up-
per address inputs to determine the accesd block. ADV# LOW opens the internal ad-
dress latches. OE# LOW activates the outputs and gates lected data onto the I/O bus.
Bus cycles to/from the device conform to standard microprocessor bus operations. Bus
operations and the logic levels that must be applied to the device control signal inputs
are shown here.
Table 9: Bus Operations
Notes: 1.Refer to the Device Command Bus Cycles for valid DQ[15:0] during a WRITE operation.
2.X = "Don’t Care" (H or L).
3.RST# must be at V SS ± 0.2V to meet the maximum specified power-down current. Read
To perform a READ operation, RST# and WE# must be de-asrted while CE# and OE#
are asrted. CE# is the device-lect control. When asrted, it enables the device. OE#
is the data-output control. When asrted, the addresd flash memory data is driven
onto the I/O bus.
Write
To perform a WRITE operation, both CE# and WE# are asrted while RST# and OE# are
de-asrted. During a WRITE operation, address and data are latched on the rising edge
of WE# or CE#, whichever occurs first. The Command Bus Cycles table shows the bus
cycle quence for each of the supported device commands, while the Command Codes
and Definitions table describes each command.
Note: WRITE operations with invalid V CC and/or V PP voltages can produce spurious re-
sults and should not be attempted.
Output Disable
When OE# is de-asrted, device outputs DQ[15:0] are disabled and placed in High-Z
state, WAIT is also placed in High-Z.
Standby
When CE# is de-asrted the device is delected and placed in standby, substantially
reducing power consumption. In standby, the data outputs are placed in High-Z, inde-
Figure 12: Block Locking State Diagram
Program/Era Allowed科目四考试试题
WP# = V IL = 0
樱桃吃多了
WP# = V IL = 0
Program/Era Prevented
凉拌黄瓜片Program/Era Prevented
WP# = V IH = 1
Program/Era Allowed
WP# = V IH = 1
Note:
什么给我的启示1.D0h = UNLOCK command; 01h = LOCK command; 60h (not shown) LOCK SETUP com-mand; 2Fh = LOCK DOWN command.
Block Locking During Suspend
Block lock and unlock changes can be performed during an era suspend. To change
共创文明城市
人武学院block locking during an ERASE operation, first issue the ERASE SUSPEND command.Monitor the status register until SR7 and SR6 are t, indicating the device is suspended and ready to accept another command.
Next, write the desired lock command quence to a block, which changes the lock state of that block. After completing BLOCK LOCK or BLOCK UNLOCK operations, re-sume the ERASE operation using the ERASE RESUME command.Note:
A BLOCK LOCK SETUP command followed by any command other than BLOCK LOCK,BLOCK UNLOCK, or BLOCK LOCK DOWN produces a command quence error and t SR4 and SR5. If a command quence error occurs during an era suspend, SR4 and SR5 remains t, even after the era operation is resumed. Unless the Status Register is cleared using the CLEAR STATUS REGISTER command before resuming the ERASE op-eration, possible era errors may be masked by the command quence error.If a block is locked or locked-down during an era suspend of the same block, the lock status bits change immediately. However, the ERASE operation completes when it is re-sumed. BLOCK LOCK operations cannot occur during a program suspend.
Figure 18: Buffer Program Procedure
Notes: 1.Word count values on DQ0:DQ15 are loaded into the count register. Count ranges for
this device are N = 0000h to 01FFh.
2.Device outputs the status register when read.
3.Write buffer contents will be programmed at the device start or destination address.
4.Align the start address on a write buffer boundary for maximum programming perform-
ance; that is, A[9:1] of the start address = 0).如何计算圆的面积
5.Device aborts the BUFFERED PROGRAM command if the current address is outside the
文明家庭original block address.
6.Status register indicates an improper command quence if the BUFFERED PROGRAM
command is aborted. Follow this with a CLEAR STATUS REGISTER command.
7.Device defaults to SR output data after BUFFERED PROGRAMMING SETUP command
(E8h) is issued . CE# or OE# must be toggled to update the status register . Don’t issue
the READ SR command (70h); it is interpreted by the device as buffer word count.
8.Full status check can be done after era and write quences complete. Write FFh after
the last operation to ret the device to read array mode.
Figure 19: Buffered Enhanced Factory Programming (BEFP) Procedure
Setup Pha Program and Verify Pha Exit Pha
