MCF51JF32VFM 데이터 시트보기 (PDF) - Freescale Semiconductor

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MCF51JF32VFM

Embedded - Microcontrollers

Freescale Semiconductor 

Memories and memory interfaces

Table 19. NVM reliability specifications (continued)

Symbol Description

Write endurance

nnvmwree16

nnvmwree128

nnvmwree512

nnvmwree4k

nnvmwree8k

• EEPROM backup to FlexRAM ratio = 16

• EEPROM backup to FlexRAM ratio = 128

• EEPROM backup to FlexRAM ratio = 512

• EEPROM backup to FlexRAM ratio = 4096

• EEPROM backup to FlexRAM ratio = 8192

Min.

35 K

315 K

1.27 M

10 M

20 M

Typ.1

175 K

1.6 M

6.4 M

50 M

100 M

Max.

—

—

—

—

—

Unit

writes

writes

writes

writes

writes

Notes

4

1. Typical data retention values are based on measured response accelerated at high temperature and derated to a constant

25°C use profile. Engineering Bulletin EB618 does not apply to this technology.

2. Data retention is based on Tjavg = 55°C (temperature profile over the lifetime of the application).

3. Cycling endurance represents number of program/erase cycles at -40°C ≤ Tj ≤ 125°C.

4. Write endurance represents the number of writes to each FlexRAM location at -40°C ≤Tj ≤ 125°C influenced by the cycling

endurance of the FlexNVM (same value as data flash) and the allocated EEPROM backup. Minimum and typical values

assume all byte-writes to FlexRAM.

6.4.1.5 Write endurance to FlexRAM for EEPROM

When the FlexNVM partition code is not set to full data flash, the EEPROM data set size

can be set to any of several non-zero values.

The bytes not assigned to data flash via the FlexNVM partition code are used by the

FTFL to obtain an effective endurance increase for the EEPROM data. The built-in

EEPROM record management system raises the number of program/erase cycles that can

be attained prior to device wear-out by cycling the EEPROM data through a larger

EEPROM NVM storage space.

While different partitions of the FlexNVM are available, the intention is that a single

choice for the FlexNVM partition code and EEPROM data set size is used throughout the

entire lifetime of a given application. The EEPROM endurance equation and graph

shown below assume that only one configuration is ever used.

Writes_FlexRAM =

EEPROM – 2 × EEESIZE

EEESIZE

× Write_efficiency × nnvmcycd

where

• Writes_FlexRAM — minimum number of writes to each FlexRAM location

• EEPROM — allocated FlexNVM based on DEPART; entered with Program

Partition command

• EEESIZE — allocated FlexRAM based on DEPART; entered with Program Partition

command

• Write_efficiency —

MCF51JF128 Data Sheet, Rev. 6, 01/2012.

30

Freescale Semiconductor, Inc.

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