Meaning of "without security" in "General Information"

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Meaning of "without security" in "General Information"

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efk
Contributor I

Hello,

 

I would like to use the MCF52252 for a new project. I need the ability to secure the flash memory, in order that it is not possible to read the flash (BDM access disable), and the only accepted function is a mass erase (via backdoor access or Ezport access). When i click on the "i" icon, in the "freescale buy" page, i see the following page (see attached picture). I am a bit confused with the mention "without security".

 

Can somebody tell me the meaning of "without security" ?

Does this means it is possible to secure the flash of only some MCF5225x devices (not all) ?

 

Regards.

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TomE
Specialist I

> It is still not clear for me.

The "with security" and "FLASH" parts of the description have ABSOLUTELY NOTHING to do with each other. The "Description" is a very short "chip feature list"

Part Number    MCF52252CAF66

Description    100LQFP 256K FLASH WITHOUT SECURITY

Long Description: Package is 100LQFP. There's 256k of FLASH. This chip DOES NOT have the CAU "Security Module".

Part Number    MCF52255CAF80

Description    100LQFP 512K FLASH WITH SECURITY


Long Description: Package is 100LQFP. There's 512k of FLASH. This chip DOES have the CAU "Security Module".

So it is "256k FLASH <COMMA OR FULL STOP> WITHOUT SECURITY" and not "256k (FLASH WITHOUT SECURITY)".

Tom

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TomE
Specialist I

I can't get to that page from the screen snapshot you've provided, so I can't check my ideas.

I find it a very confusing summary line too.

The MCF5225x range consists of parts 2, 4, 5, 6, 8, 9. The different parts have different amounts of RAM, ROM and certain peripherals, specifically the Random Number Generator and Cryptographic units.

Could you please see if the pages for the "56" and "59" DON'T have "without security" and the others do? In that case "256k FLASH WITHOUT SECURITY" really means "variant with 256k of FLASH memory, but without the CAU security module".

Searching for "without security" in other Freescale documents shows up the following document for the MPC8536E:

http://www.freescale.com/files/32bit/doc/errata/MPC8536ECE.pdf

That document doesn't explain "without security", but the Data Sheet details that it means "with and without the Security Engine".

Tom

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efk
Contributor I

Thank you for your answer.

The link is: http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=MCF5225X&nodeId=018rH3YTLC00M95448&ta...

The attached picture "info" shows where i click to see the "details" page.

Here is the "flash security" detail for each device:

Part Number    MCF52252AF80

Description    100LQFP 256K FLASH WITHOUT SECURITY

Part Number    MCF52252CAF66

Description    100LQFP 256K FLASH WITHOUT SECURITY

Part Number    MCF52254AF80

Description    100LQFP 512K FLASH WITHOUT SECURITY

Part Number    MCF52254CAF66

Description    100LQFP 512K FLASH WITHOUT SECURITY

Part Number    MCF52255CAF80

Description    100LQFP 512K FLASH WITH SECURITY

Part Number    MCF52256AG80

Description    KIRIN3 144LQ 256K FLASH WITHOUT SECURITY

Part Number    MCF52256CAG66

Description    KIRIN3 144LQ 256K FLASH WITHOUT SECURITY

Part Number    MCF52256CVN66

Description    256K FLASH WITH SECURITY

Part Number    MCF52258AG80

Description    KIRIN3 144LQ 512K FLASH WITHOUT SECURITY

Part Number    MCF52258CAG66

Description    KIRIN3 144LQ 512K FLASH WITHOUT SECURITY

Part Number    MCF52258CVN66

Description    512K FLASH WITHOUT SUCURITY

Part Number    MCF52258VN80

Description    512K FLASH WITHOUT SECURITY

Part Number    MCF52259CAG80

Description    KIRIN3 144LQFP 512K FLASH WITH SECURITY

Part Number    MCF52259CVN80

Description    512K FLASH WITH SECURITY

Part Number    PCF52255CAF80

Description    512K FLASH WITH SECURITY

Part Number    MCF52258CVN66J

Description    512K FLASH WITHOUT SUCURITY

Part Number    MCF52258VN80J

Description    512K FLASH WITHOUT SECURITY

Part Number    MCF52259CVN80J

Description    512K FLASH WITH SECURITY

It says: MCF52252, MCF52259 and one of the MCF52256 have "flash security" !

It is still not clear for me.

Can you please tell me your mind ?

Regards.

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TomE
Specialist I

> It is still not clear for me.

The "with security" and "FLASH" parts of the description have ABSOLUTELY NOTHING to do with each other. The "Description" is a very short "chip feature list"

Part Number    MCF52252CAF66

Description    100LQFP 256K FLASH WITHOUT SECURITY

Long Description: Package is 100LQFP. There's 256k of FLASH. This chip DOES NOT have the CAU "Security Module".

Part Number    MCF52255CAF80

Description    100LQFP 512K FLASH WITH SECURITY


Long Description: Package is 100LQFP. There's 512k of FLASH. This chip DOES have the CAU "Security Module".

So it is "256k FLASH <COMMA OR FULL STOP> WITHOUT SECURITY" and not "256k (FLASH WITHOUT SECURITY)".

Tom

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efk
Contributor I

Thank you very much for your extended explaination.

It is now clear for me.

Regards.

Bob

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alager
Contributor II

FWIW:

Looking at the 52259 chip, which does have the CAU, "cryptographic acceleration unit", the description is "with security"

EDIT: I just saw the bottom of your last post, you already knew this.....