How to protect code in 16f877a

[picgak]

Hi,

How can we protect the programmed code from being read back or erased using JAL , I am using the bert library . can someone explain this in detail.

Thank you

Regards ani

[Joep Suijs]

Hi Ani,

I'n not sure if erase protection (from an external programmer) is
possible. Having said that, the features you want to use are set with
the 'configuration words' of a pic and are explained in detail in the
datasheet of the pic you use.
Configuration word settings are also refered to as 'fuses' and are set
in JAL with the 'pragma target' command. How exactly is determined by
the device files you are using.
Since you aren't using jallib device files (and have not mentioned
which pic you use), I can't help you on this. I suggest you ask your
question on the jallist (http://tech.groups.yahoo.com/group/jallist/).

Joep


2012/10/3 picgak <ani...@gmail.com>:

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[picgak]

Hi Joep,

I am using 16f877A  the following portion of code is from the bert libray for 16f877a 

include 16f877a_inc_all

pragma target clock       20_000_000

const word _fuses         = 0x3fff ; default value

pragma target osc         hs

pragma target watchdog    off

-- HS, -BOD, ,-LVP, -WDT, -CP  = 0x3F22

pragma target fuses       0x3F32

To protect the code should I change something in this portion  -CP  = 0x3F22

Regards ani

[Joep Suijs]

Let me repeat part of of my reply ;)

> Since you aren't using jallib device files (...), I can't help you on

[picgak]

On Wednesday, October 3, 2012 7:34:50 PM UTC+5:30, picgak wrote:

Hi,

In Jallib how do we protect the code written on it

Thank you

Regards ani

 

[vasile surducan]

Hi, take the datasheet of the PIC16F877A and read how to protect de
code at page 144, bit 10-9

http://ww1.microchip.com/downloads/en/devicedoc/39582b.pdf

then transform all the binary sequence there in hex and replace your
value which is 0x3F22 with the new one

Vasile

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[Rob Hamerling]

On 13-11-12 13:10, picgak wrote:

> On Wednesday, October 3, 2012 7:34:50 PM UTC+5:30, picgak wrote:
>
> In Jallib how do we protect the code written on it

Have a look in the device file. The last pragma is what you need to use
in your program. Hopefully you'll agree that:
pragma TARGET CP ENABLE
is what you are looking for.

Regards, Rob.


--
R. Hamerling, Netherlands --- http://www.robh.nl

[picgak]

Thanks Vasile and RobH for your quick and informative replay

Regards ani