PA28F800B5-T90 查看數據表（PDF） - Intel

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PA28F800B5-T90

SMART 5 BOOT BLOCK FLASH MEMORY FAMILY 2, 4, 8 MBIT

Intel 

SMART 5 BOOT BLOCK MEMORY FAMILY

E

3.3 Boot Block Locking

The boot block family architecture features a

hardware-lockable boot block so that the kernel

code for the system can be kept secure while the

parameter and main blocks are programmed and

erased independently as necessary. Only the boot

block can be locked independently from the other

blocks.

3.3.1

VPP = VIL FOR COMPLETE

PROTECTION

For complete write protection of all blocks in the

device, the VPP voltage can be held low. When VPP

is below VPPLK, any program or erase operation will

result in a error in the status register.

3.3.2

WP# = VIL FOR BOOT BLOCK

LOCKING

When WP# = VIL, the boot block is locked and any

program or erase operation to the boot block will

result in an error in the status register. All other

blocks remain unlocked in this condition and can be

programmed or erased normally. Note that this

feature is overridden and the boot block unlocked

when RP# = VHH.

3.3.3

RP# = VHH OR WP# = VIH FOR BOOT

BLOCK UNLOCKING

Two methods can be used to unlock the boot block:

1. WP# = VIH

2. RP# = VHH

If both or either of these two conditions are met, the

boot block will be unlocked and can be

programmed or erased.

The Write Proctection Truth Table, Table 8, clearly

defines the write protection methods.

3.3.4

NOTE FOR 8-MBIT 44-PSOP

PACKAGE

The 8-Mbit in the 44-PSOP package does not have

a WP# because no other pins were available for the

8-Mbit upgrade address. Thus, in this density-

package combination only, VHH (12 V) on RP# is

required to unlock the boot block and unlocking with

a logic-level signal is not possible. If this unlocking

functionality is required, and 12 V is not available

in-system, please consider using the 48-TSOP

package, which has a WP# pin and can be

unlocked with a logic-level signal. All other density-

package combinations have WP# pins.

Table 8. Write Protection Truth Table

VPP RP# WP#

Write Protection

Provided

VIL

X

≥ VPPLK VIL

X All Blocks Locked

X All Blocks Locked

(Reset)

≥ VPPLK

≥ VPPLK

≥ VPPLK

VHH

VIH

VIH

X All Blocks Unlocked

VIL Boot Block Locked

VIH All Blocks Unlocked

4.0 DESIGN CONSIDERATIONS

The following section discusses recommended

design considerations which can improve the

robustness of system designs using flash memory.

4.1 Power Consumption

Intel flash components contain features designed to

reduce power requirements. The following sections

will detail how to take advantage of these features.

4.1.1

ACTIVE POWER

Asserting CE# to a logic-low level and RP# to a

logic-high level places the device in the active

mode. Refer to the DC Characteristics table for ICCR

current values.

4.1.2

AUTOMATIC POWER SAVINGS (APS)

Automatic Power Savings (APS) provides low-

power operation in active mode. Power Reduction

Control (PRC) circuitry allows the device to put

itself into a low current state when not being

accessed. After data is read from the memory

array, PRC logic controls the device’s power

consumption by entering the APS mode where

typical ICC current is less than 1 mA. The device

stays in this static state with outputs valid until a

new location is read.

24

ADVANCE INFORMATION

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