Comments on: How important are reference designs? http://www.embeddedinsights.com/channels/2011/09/28/how-important-are-reference-designs/ Shedding Light on the Hidden World of Embedded Systems Mon, 28 Jul 2014 16:18:37 -0400 hourly 1 http://wordpress.org/?v=3.0 By: D. @ LI http://www.embeddedinsights.com/channels/2011/09/28/how-important-are-reference-designs/#comment-8848 D. @ LI Sat, 29 Oct 2011 03:32:07 +0000 http://www.embeddedinsights.com/channels/?p=636#comment-8848 Good reference designs are valuable to me because microprocessors are not that easy to program or to use as they have been decades ago. Some microprocessors can't be used without software examples, which are a first step to reference design. Rockwell did a great job with the AIM 65 and the CO-ED programmer, and then with the RM65 series boards. All aspects of a microprocessor systems, each with it's own PCB and software, well documented and immediately to be used. I never saw such a sophisticated reference design ever since. Now I am using Forth for my projects. With Forth I can evaluate a new microprocessor interactively. Good reference designs are valuable to me because microprocessors are not that easy to program or to use as they have been decades ago. Some microprocessors can’t be used without software examples, which are a first step to reference design.

Rockwell did a great job with the AIM 65 and the CO-ED programmer, and then with the RM65 series boards. All aspects of a microprocessor systems, each with it’s own PCB and software, well documented and immediately to be used. I never saw such a sophisticated reference design ever since.

Now I am using Forth for my projects. With Forth I can evaluate a new microprocessor interactively.

]]> By: R. @ LI http://www.embeddedinsights.com/channels/2011/09/28/how-important-are-reference-designs/#comment-8762 R. @ LI Tue, 25 Oct 2011 00:35:15 +0000 http://www.embeddedinsights.com/channels/?p=636#comment-8762 Many good points above! One slight side-issue this made me think of - some vendors (Infineon comes to mind) produce software to "auto-generate" the initialisation code from some set of more user-friendly set-up (e.g. this PWM channel is at 1kHz). Such tools are IN NO WAY a substitute for a properly documented "reference design". At best they generate truly ugly code that almost does the job and nearly fits into a system not dissimilar from what you're building. At the end of the day, all you can do with what they produce is try to use it as if it were a reference design, but since it's so badly structured and undocumented, that's no easy task. Many good points above!
One slight side-issue this made me think of – some vendors (Infineon comes to mind) produce software to “auto-generate” the initialisation code from some set of more user-friendly set-up (e.g. this PWM channel is at 1kHz). Such tools are IN NO WAY a substitute for a properly documented “reference design”. At best they generate truly ugly code that almost does the job and nearly fits into a system not dissimilar from what you’re building. At the end of the day, all you can do with what they produce is try to use it as if it were a reference design, but since it’s so badly structured and undocumented, that’s no easy task.

]]> By: S. @ LI http://www.embeddedinsights.com/channels/2011/09/28/how-important-are-reference-designs/#comment-8687 S. @ LI Thu, 20 Oct 2011 06:11:53 +0000 http://www.embeddedinsights.com/channels/?p=636#comment-8687 @A. I've been there too. You want to be responsible for your own design by knowing every aspect of your modules and not take in 3rd party baggage. That's what I did in my last project. However, when it comes to more complex chips where much of the firmware resides on the host processor, the vendor's firmware is part of the total solution. For example a media chip or a LLC chip. You're at the mercy of the vendor to provide the patches and conformance. You hope that they are as good as they claimed to be. It sounds like that vendor did a super poor job with their firmware. @A. I’ve been there too. You want to be responsible for your own design by knowing every aspect of your modules and not take in 3rd party baggage. That’s what I did in my last project. However, when it comes to more complex chips where much of the firmware resides on the host processor, the vendor’s firmware is part of the total solution. For example a media chip or a LLC chip. You’re at the mercy of the vendor to provide the patches and conformance.
You hope that they are as good as they claimed to be. It sounds like that vendor did a super poor job with their firmware.

]]> By: A. @ LI http://www.embeddedinsights.com/channels/2011/09/28/how-important-are-reference-designs/#comment-8686 A. @ LI Thu, 20 Oct 2011 06:11:31 +0000 http://www.embeddedinsights.com/channels/?p=636#comment-8686 There can be support difficulties even if you do base your hardware and software on their reference design. The moment you make any changes to the reference design they start saying that you should reproduce any problems using their hardware and software before they will investigate. This isn't always easy to do, especially if you are using features and functions that are not supported by the reference design. Another nasty surprise they can spring on you is to re-architect their software in update releases. Once you've made any significant level of adaptation to the code in a previous release, taking the new release (which is usually necessary if you want bug fixes or enhancements) becomes a significant task. You have to understand the new architecture, how it maps on to the old one and work out how to port your changes to it. All of which leaves you in much the same state that you were in before, but still with a shedload of regression testing to do. We've been on the receiving end of both of these experiences in the past 48 hours so as you might expect I'm feeling a touch aggrieved! There can be support difficulties even if you do base your hardware and software on their reference design. The moment you make any changes to the reference design they start saying that you should reproduce any problems using their hardware and software before they will investigate. This isn’t always easy to do, especially if you are using features and functions that are not supported by the reference design.

Another nasty surprise they can spring on you is to re-architect their software in update releases. Once you’ve made any significant level of adaptation to the code in a previous release, taking the new release (which is usually necessary if you want bug fixes or enhancements) becomes a significant task. You have to understand the new architecture, how it maps on to the old one and work out how to port your changes to it. All of which leaves you in much the same state that you were in before, but still with a shedload of regression testing to do.

We’ve been on the receiving end of both of these experiences in the past 48 hours so as you might expect I’m feeling a touch aggrieved!

]]> By: S. @ LI http://www.embeddedinsights.com/channels/2011/09/28/how-important-are-reference-designs/#comment-8685 S. @ LI Thu, 20 Oct 2011 06:11:05 +0000 http://www.embeddedinsights.com/channels/?p=636#comment-8685 I agree with everyone's comments. The reference design is valuable as a working starting point and proof for your design. A reference software can be as little as a bunch of test modules to a full set of scalable modules. You need a reference software and hardware to work on while waiting on your prototype board. I've never seen a vendor not offering a reference design. Sometimes you can extract what you need into your own design. Sometimes the chip is so complex that you need to work from their firmware foundation especially if you don't want to void their support. I agree with everyone’s comments. The reference design is valuable as a working starting point and proof for your design. A reference software can be as little as a bunch of test modules to a full set of scalable modules. You need a reference software and hardware to work on while waiting on your prototype board. I’ve never
seen a vendor not offering a reference design.
Sometimes you can extract what you need into your own design. Sometimes the chip is so complex that you need to work from their firmware foundation especially if you don’t want to void their support.

]]> By: F. @ LI http://www.embeddedinsights.com/channels/2011/09/28/how-important-are-reference-designs/#comment-8665 F. @ LI Wed, 19 Oct 2011 06:53:42 +0000 http://www.embeddedinsights.com/channels/?p=636#comment-8665 I agree with A.'s observations. The only stuff that will work on the reference design is the stuff that ALREADY works on the reference design. i.e. the default. At least it can help. I agree with A.’s observations. The only stuff that will work on the reference design is the stuff that ALREADY works on the reference design. i.e. the default. At least it can help.

]]> By: B. @ LI http://www.embeddedinsights.com/channels/2011/09/28/how-important-are-reference-designs/#comment-8614 B. @ LI Sun, 16 Oct 2011 15:17:17 +0000 http://www.embeddedinsights.com/channels/?p=636#comment-8614 ST had a habit of publishing reference designs, then refusing to publish the software that ran the demo. They claimed they could not give it out due to license restrictions. ST had a habit of publishing reference designs, then refusing to publish the software that ran the demo. They claimed they could not give it out due to license restrictions.

]]> By: A. @ LI http://www.embeddedinsights.com/channels/2011/09/28/how-important-are-reference-designs/#comment-8609 A. @ LI Sat, 15 Oct 2011 23:40:40 +0000 http://www.embeddedinsights.com/channels/?p=636#comment-8609 In my experience reference designs aren't thorougly tested. They are usually put together in a hurry to provide a sales and marketing platform for a new device and as a consequence are buggy and incomplete. Support is usually sporadic and often stops altogether once the next generation device is launched, even if the vendor is still actively promoting older generations. The software is invariably badly written and poorly commented and documentation (if any) is incomplete, incorrect and out of date. Functionality is generally restricted to those features that are required for demonstrations and features that aren't immediately visible to the user, such as power management, are typically not implemented at all or implemented so badly that you have to do them again from scratch to get them to work. Of course some vendors are better than others, but I have yet to find a reference design that does not suffer from at least some of these problems. On the plus side, a reference design is a far better starting point for your own product than a blank sheet of paper. You know that most of the hardware will work, at least in its default configuraion, even if it isn't optimal. The software will at least boot up and allow you to interact with the system. So it's a great deal better than nothing, but still, you gets what you pays for. In my experience reference designs aren’t thorougly tested. They are usually put together in a hurry to provide a sales and marketing platform for a new device and as a consequence are buggy and incomplete. Support is usually sporadic and often stops altogether once the next generation device is launched, even if the vendor is still actively promoting older generations. The software is invariably badly written and poorly commented and documentation (if any) is incomplete, incorrect and out of date.

Functionality is generally restricted to those features that are required for demonstrations and features that aren’t immediately visible to the user, such as power management, are typically not implemented at all or implemented so badly that you have to do them again from scratch to get them to work. Of course some vendors are better than others, but I have yet to find a reference design that does not suffer from at least some of these problems.

On the plus side, a reference design is a far better starting point for your own product than a blank sheet of paper. You know that most of the hardware will work, at least in its default configuraion, even if it isn’t optimal. The software will at least boot up and allow you to interact with the system. So it’s a great deal better than nothing, but still, you gets what you pays for.

]]> By: K. @ LI http://www.embeddedinsights.com/channels/2011/09/28/how-important-are-reference-designs/#comment-8572 K. @ LI Thu, 13 Oct 2011 21:38:44 +0000 http://www.embeddedinsights.com/channels/?p=636#comment-8572 I have used reference designs mainly to clarify points where the documentation is unclear, such as EXACTLY what a particular pin is for, and how it should be used, and to give me confidence that the component will be completely suitable for my purpose. Occasionally I've used them as a test configuration for detailed performance testing with samples. Sometimes they're useful for suggesting auxiliary components. They are always valuable, because, I assume, they have been thoroughly tested and found to work well. I also agree with Franz's comment. I have used reference designs mainly to clarify points where the documentation is unclear, such as EXACTLY what a particular pin is for, and how it should be used, and to give me confidence that the component will be completely suitable for my purpose. Occasionally I’ve used them as a test configuration for detailed performance testing with samples. Sometimes they’re useful for suggesting auxiliary components. They are always valuable, because, I assume, they have been thoroughly tested and found to work well. I also agree with Franz’s comment.

]]> By: R. @ LI http://www.embeddedinsights.com/channels/2011/09/28/how-important-are-reference-designs/#comment-8571 R. @ LI Thu, 13 Oct 2011 21:38:24 +0000 http://www.embeddedinsights.com/channels/?p=636#comment-8571 Vendor demo/prototype boards have been very valuable because they let us start on our port and development early. We have been able breadboard some of our peripherals for additional benefit. I maintained the BSP for the prototype board in the product base code for years, just in case we wanted to try an upgraded CPU with a new prototype board. The paper reference designs can be a good start or just a sanity check against our own paper design. And, I collect all of the application notes; engineers may collect tips for years before tech pubs does an update. There's more -- I don't know about other vendors, but Freescale provides a configuration tool for its more complex microcontrollers. This tool helps refine the legal as well as desired desired periperal set, tradeoffs and pinout. It can save weeks studying the documentation, and much head scratching. All of these help us reduce risk and improve time-to-market. Vendor demo/prototype boards have been very valuable because they let us start on our port and development early. We have been able breadboard some of our peripherals for additional benefit. I maintained the BSP for the prototype board in the product base code for years, just in case we wanted to try an upgraded CPU with a new prototype board. The paper reference designs can be a good start or just a sanity check against our own paper design. And, I collect all of the application notes; engineers may collect tips for years before tech pubs does an update. There’s more — I don’t know about other vendors, but Freescale provides a configuration tool for its more complex microcontrollers. This tool helps refine the legal as well as desired desired periperal set, tradeoffs and pinout. It can save weeks studying the documentation, and much head scratching. All of these help us reduce risk and improve time-to-market.

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