ARM-based platforms are a foreign offer to most users of inserted PC boards. But it?s clear that in terms of performance at least, ARM solutions are now analogous with x86. So what would be the other key issues which might lead an embedded P.C user to cross the divide?
The most blatant underlying difference is quite fundamental. PERSONAL COMPUTER boards rely on standard form-factors and bus interfaces, whereas extraordinarily little in the way of standards is apparent when taking a look at ARM-based boards. On initial inspection, this might look like a clear advantage for embedded Computers, but when you look a touch more deeply , it?s not quite what it seems.
ARM microcontrollers are complete systems-on-chip (SoC). With the exception of memory, everything is on there the Ethernet MAC, the LCD controller, USB, UARTs, SD Card, CAN, Audio, touch? You name it. So there is no real point in outlining standard bus interfaces to the outside world when you commence with a total system in itself. ? These system-on-chip micros provide a longevity of 10 years or longer. So you purchase a particular board or module with the aim of using it for the length of the project. Against this, x86 boards may?have a market lifetime?as small as one or two years, and you depend on the standard interface and form factor to permit replacement in the project life cycle.
The COM (Computer-on-Module) is by far the most typical conveyance for ARM-based boards, which, due to the level of integration of the SoC could be credit-card, or even matchbox sized. In the ARM-based world the acronym SOM (System-on-Module) is commonly used to distinguish the completeness of the solution from the COM. But just like a COM, a breakout or baseboard is then needed to complete the solution.
There are many SOMs to choose from but there's a very limited choice of ARM-based SBCs out there, simply because of the actual number and diversity of interfaces offered by a common SoC. If you brought them all to connectors, the SBC would need to be a foot square, so better to bring a good selection of them to a single 200-pin SODIMM style interface (the most well-liked solution, although not using any standard pinout) and let the user customize the breakout.
If your inserted Personal computer is running Windows, whether the desktop or the embedded version (Windows Embedded Standard) there is good news and bad news. The interesting news is the licence cost of Windows Embedded CE or Compact 7will likely be less than a 10% of what you’re paying now. The bad news is simply that for the majority of situations, the programming environment is a subset, and so work must be done. In particular, your .NET applications will have to be shoehorned into .NET Compact Framework. If you?re using WPF, again subsetting into a special inserted version of Silverlight is needed.
A downside of the ARM-based route is that unlike the embedded COMPUTER where once Windows is running you can develop your application without any special data, with Windows CE or Compact 7, you need a top quality Board Support Package (BSP) from the seller, and may need their aid, and even some coaching, to utilise a special tool called Platform Builder which combines library elements of the OS, the BSP, plus your request to make a production image. Remember all those interfaces on the SoC Well, the BSP is componentized and there is no presumption that all of the interfaces will be supported, or that the ones that are supported will work in the way you expect. So that the production-readiness Of the BSP is as important as hardware features and price when selecting. Naturally, many ARM-based projects use Linux, and exactly the same necessities apply, although your seller may shrug his shoulders and point at the opensource community if you need more than they offer, which
isn’t truly useful. If you?re using Windows CE, you may depend on Microsoft’s well-managed qualification scheme? In which case selecting a Windows Inserted
Gold Partner as your supplier should be an absolute minimum duty.
Cost-wise, as volume increases, the ARM-based solution wins every time. ARM-based devices are cheap, and as fast as your volume will eclipse the engineering cost connected with producing a custom baseboard, you are winning all of the way.
Another significant benefit of an ARM-based solution is energy usage. A normal platform will consume around 1W, so no fans required, and it’s brilliantly feasible
to make your own handheld device. A little, fanless solution, can bring competitive advances. Even when not handheld. As an example, having the ability to offer hours of power-failure backup via a tiny integrated battery will beat a competitor who relies on a pricey external UPS. Miniscule systems are also way easier to ruggedize.
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