您的位置：维库电子市场网 > Datasheet > PIC16F871

PIC16F871 Datasheet

  • PIC16F871

  • 28/40-Pin, 8-Bit CMOS FLASH Microcontrollers

  • 1755.40KB

  • 172页

  • Microchip   Microchip

阅览下载 纠错 0

扫码查看芯片数据手册

上传产品规格书

PDF预览

PIC16F870/871
4.7
Write Verify
4.9
Operation during Code Protect
Depending on the application, good programming prac-
tice may dictate that the value written to the memory
should be verified against the original value. This
should be used in applications where excessive writes
can stress bits near the specification limit.
Generally a write failure will be a bit which was written
as a 鈥?鈥? but reads back as a 鈥?鈥?(due to leakage off the
bit).
Each reprogrammable memory block has its own code
protect mechanism. External Read and Write opera-
tions are disabled if either of these mechanisms are
enabled.
4.9.1
DATA EEPROM MEMORY
4.8
4.8.1
Protection Against Spurious Write
EEPROM DATA MEMORY
The microcontroller itself can both read and write to the
internal Data EEPROM, regardless of the state of the
code protect configuration bit.
When data memory is code protected (CONFIG<8>=0)
any further external programming access of program
memory is disabled. To reenable programming access
to program memory, both bulk erase and removal of
code protection must be performed on program and
data memory.
4.9.2
PROGRAM FLASH MEMORY
There are conditions when the device may not want to
write to the data EEPROM memory. To protect against
spurious EEPROM writes, various mechanisms have
been built-in. On power-up, the WREN bit is cleared.
Also, the Power-up Timer (72 ms duration) prevents
EEPROM write.
The write initiate sequence and the WREN bit together
help prevent an accidental write during brown-out,
power glitch, or software malfunction.
4.8.2
PROGRAM FLASH MEMORY
To protect against spurious writes to FLASH program
memory, the WRT bit in the configuration word may be
programmed to 鈥?鈥?to prevent writes. The write initiate
sequence must also be followed. WRT and the configu-
ration word cannot be programmed by user code, only
through the use of an external programmer.
The microcontroller can read and execute instructions
out of the internal FLASH program memory, regardless
of the state of the code protect configuration bits. How-
ever, the WRT configuration bit and the code protect
bits have different effects on writing to program mem-
ory. Table 4-1 shows the various configurations and
status of reads and writes. To erase the WRT or code
protection bits in the configuration word requires that
the device be fully erased.
TABLE 4-1:
READ/WRITE STATE OF INTERNAL FLASH PROGRAM MEMORY
Memory Location
Internal
Read
Yes
Yes
Yes
Yes
Internal
Write
Yes
No
No
Yes
ICSP Read ICSP Write
No
No
Yes
Yes
No
No
Yes
Yes
Configuration Bits
CP1
0
0
1
1
CP0
0
0
1
1
WRT
1
0
0
1
All program memory
All program memory
All program memory
All program memory
DS30569A-page 44
Preliminary
漏
1999 Microchip Technology Inc.

PIC16F871相关型号PDF文件下载

您可能感兴趣的PDF文件资料

热门IC型号推荐

©2024 维库电子市场网（www.dzsc.com）　备案号：浙B2-20050339-1 经营许可证：浙B2-20210386版权声明
买家服务热线：0571-85317607 | 买家服务部QQ： QQ:1609526468
卖家服务热线：0571-85317607 | 卖家服务部QQ： QQ:331652727

扫码下载APP，
一键连接广大的电子世界。

在线人工客服

买家服务：
卖家服务：

0571-85317607

客服在线时间周一至周五
9:00-17:30

关注官方微信号，
第一时间获取资讯。

建议反馈
返回顶部

建议反馈

联系人：

联系方式：

按住滑块，拖拽到最右边
>>
感谢您向阿库提出的宝贵意见，您的参与是维库提升服务的动力！意见一经采纳，将有感恩红包奉上哦！

PDF纠错X

投诉电话：0571-85317607 投诉QQ：

如选匿名将无法为您反馈投诉结果，建议实名投诉！