Soft Class-C to freescale microprocessors

[Eneko]

Hello:

I have a little problem and I don´t know exactilly if you can help me but I have to try because at this moment I’m lossed.

We’re developing  a new product and in our first discussions with  homologation institutes they have said to us that our software has to be necessary “SOFT- Class C”. This kind of software is very special because demands to the programmer a lot of considerations about the security of microprocessor.

This soft demands me to control CPU registers ( with WALPAT routines for example), Programme counter ,addressing, clock, invariable memory internal or external (cyclic redundancy test->CRC8) , timer , etc.

My question is:

¿Do you have developed any routines or libraries which control some possibles CPUs errors , clock errors or memory errors, etc? Is there any application note with some kind of questions?

Let me know please. I have to develop this project with the micro MC9S08AW16.

Eneko Muguerza

Copreci S.Coop.

Spain

[alex_spotw]

Hi:

Could you let us know what homologation is SOFT- Class C? Which institute, etc?

There are some routines to do some of the things you are requested, but may be more information about it, would help us guide you.

Regards,

Alex

[Eneko]

Hi Alex:

We develop electronic circuits to whitegoods. Our electronic can control:

vitroceramic heaters, gas heaters and induction heaters. My case is the 3rd but my collegues will be start working with thw soft class-C in gas heaters and vitroceramics ( the last step) soon.

depends on the application and the final client, we usually homologate our products in these institutes. IMQ(Italy) to gas control , LCOE(spain) to induction and VDE (germany) to vitroceramics. We have to observe the normative IEC 60730 aptdo H whict talks about how is necessary to test the microprocessor operation.

I enclose to you the example guide that is included in this manual. Is my guide because as I have said in my e-mail before, I´m lossed because I´m working without any reference.

I hope this information would be usefull.

Many thanks in advance.

Best regards

Eneko

soft_class_c_example.pdf

Message Edited by t.dowe on 2009-09-22 11:23 AM

[alex_spotw]

Hi Eneko:

Thanks for the information.

What you need to define first is which is your minimum fault/error requirements of the acceptable measures and define which are your acceptable measures.

I checked the file and I don't think there is a single source of software to implement all the recommendations. Many items depend of your specific hardware implementation (external vs internam RAM/ROM memory, external vs internal communications devices, etc).


The first think I would do would be to check the list of recommendations versus your hardware and cross the items that would not apply. For example, it you don't have external RAM/ROM, then you don't need to check for Address lines test (Item 1.4)

Now, which MCU are you using?

Some items might require an external device to test the performace of the main MCU. Therefore, you would have to put extra hardware.

There are routines to check CRC's, memory patterns, etc, but you have to be able to provide the the code to do all those tests. For example. If you need to test the RAM memory, you need to stop your main application, store or erase the current state of all variables, run your test, and then restore the variables. You can do it periodically, in small consecutive parts of the memory.

Let us know!

Regards,

Alex
Suerte, amigo!

[Eneko]

Hi Alex:

My micro is a 9S08AW16. I don´t use external memories. I use only a internal part of flash memory as Eeprom.

As you say, I know that I have to test CPU registers (that is way I'm asking about walpat memory test) and the rest of CPU values (programe counter , etc).

I´m using a internal clock (FLL Engaged) so I have to test clock. At the same time , I need to test too Internal memory and I'll need a CRC routine to do that.

And as you say in your last e-mail I have to be able to stop programn and test RAM (I don´t know how). To make that is not necessary has to be a problemn because I have to develop a total new software to consider all these neccessary changes to achieve all the requeriments of Soft Class-C.

I hope this information will be usefull to you for help me but really, when I read this normative IEN 60730 Annex H, I found it very theorist.

Let me kmow.

Thanks in advance

Eneko

[alex_spotw]

Hi:

Check this website:

http://galeb.etf.bg.ac.yu/~vm/tutorial/vlsi/vlsi/part4.html

It contains some information about Test Patterns for RAM and ROM, among other things.

As I mentioned before, one way to implement some of the tests is to have a second microcontroller that would put some known input values, and verify that the Main MCU generates the correct output values, when in Test Mode (for testing the digital IO for example, and to work as a watchdog for the Main processor).

You have to consider also the amount of Flash Memory available. The 16K that you have right know, might not be enough to implement your application plus all the test code. In general, a rule of thumb if to have as much memory for testing as you have for application. This means that if you application is 16k, then you would need a 32k Flash part.

Remember, the first thing to do should be to establish your fault/error requirements.

Regards,

Alex

[alex_spotw]

Hi Eneko:

I just found a new application note regarding the implementation of some of the test you need.

Meeting IEC 60730 Class B
Compliance with the
MC9S08AW60

http://www.freescale.com/files/microcontrollers/doc/app_note/AN3257.pdf

Let us know if this information is good for you!

Regards,

Alex

[Eneko]

Hello:

Thank you very much and thank you for your information  but we have just this document since  ten days ago. We have started studing it and we have just asked some dudes to freescale people.

I'll said to you the news if you are interested on the information.

Thank you very much for remenber me.

Best regards

Eneko

[alex_spotw]

Hi:

You're welcome.

Please let me know what information you got, because I am quite interested in the MCU Fault Testing.

Regards,

Alex