Re: [SystemSafety] Development of code for ASICs under IEC 61508

From: Matthew Squair < >
Date: Fri, 5 Jul 2013 08:54:10 +1000


For me the core problem I see with VHDL and FPGA when used in combination is that they allow designers to treat hardware as software. So rather than generating a design through the classical hardware design process, where you design by analysis and prove as you go designers end up trying design concepts and just adding stuff to make it work ala software style. That of course increases the complexity and opaqueness of the design. Add in the problem that VHDL hides design detail and is not WYSIWG in nature and you can end up loosing control of what you are doing.

On Thu, Jul 4, 2013 at 5:47 PM, SPRIGGS, John J <John.SPRIGGS_at_xxxxxx

> In a previous job, I was advised by a Regulator that if I were to design
> a device using hardware techniques, e.g. describing it using NAND gates on
> a circuit diagram, then I should assure it as a piece of hardware, but if I
> were to design it using software techniques, e.g. describing it in VHDL,
> then I should assure it as if it were a piece of software.****
>
> ** **
>
> ** **
>
> John****
>
> ** **
>
> *From:* systemsafety-bounces_at_xxxxxx > systemsafety-bounces_at_xxxxxx >
> *Sent:* 02 July 2013 17:32
> *To:* systemsafety_at_xxxxxx > *Subject:* [SystemSafety] Development of code for ASICs under IEC 61508***
> *
>
> ** **
>
> Dear Colleagues
>
> I have a question about code developed for ASICs under IEC 61508:2010. IEC
> 61508-2 specifies that an ASIC development life cycle shall be used and
> notes the similarity between the software and ASIC life cycles (7.1.3.1
> Note 2). However, there is a concern that the standard's requirements for
> the ASIC life cycle appear to be less than those for software. For example,
> IEC 61508-3 specifies requirements for tools, including programming
> languages in para 7.4.4. On the other hand, IEC 61508-2 is less forthcoming
> on the issue of tools. It cross refers to para 7.4.4.2 of IEC 61508-3 in
> 7.8 the section on modification (7.8.2.3), and also mentions in Table B6
> (normative) *Use of tools that are proven in use (see 7.4.10) or
> validated; general computer aided development for all phases of the safety
> lifecycle.*
>
> Thus, should one interpret the standard along the lines that when one
> needs to certify an ASIC against IEC 61508-2, then it must also be the case
> that the ASIC code complies with IEC 61508-3 as well?
>
>
>
> ****
>
> -- ****
>
> Kind regards****
>
> ** **
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> Martin Lloyd****
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> martin.farside_at_xxxxxx >
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-- 
*Matthew Squair*
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Email: MattSquair_at_xxxxxx



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Received on Fri Jul 05 2013 - 00:54:20 CEST

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