Comments on: Hardware costs versus development costs

By: ashleigh

ashleigh — Tue, 26 Jan 2010 01:47:54 +0000

These kind of trade-offs are rarely considered.Even on salary, engineering costs your employer (where I live, its more in the USA) $100 / HOUR.It does not take many hours to burn up the cost saving made in a cheaper part.Bean counters tend to see the cost on the BOM and get up tight about it, and ignore the cost of labour. Until a consultant is involved.All engineers should get better at looking at the cost trade-offs.In one of the designs I worked on we used a processor costing $5 more than we could have go away with, because at about 1000 pieces / year, the engineering time trade off amount to $5K. We would burn through that in labour in a week. And the cheaper part would have meant spending months more on coding.

By: Nigel Jones

Nigel Jones — Wed, 13 Jan 2010 12:49:14 +0000

I use Embedded Workbench from IAR running on XP. I agree with your comment. For further thoughts on free tools and the like, you might want to check out this posting that I did a while back: http://www.embeddedgurus.net/stack-overflow/2008/09/low-cost-tools.html

By: Goldfish

Goldfish — Wed, 13 Jan 2010 10:04:51 +0000

Hi Nigel,What IDE do you use to develop for AVR, and on what OS?I'm curious, because an IDE can be one of the biggest time savers in development, and I think AVR studio leaves a lot to be desired, although admittedly I haven't used it ectensively.

By: Anders

Anders — Fri, 08 Jan 2010 10:01:14 +0000

Miro Samek's article is very interesting and is much in line with what we see. However, I think that his observation on the sweet spot for ISAs can be extended a bit if one looks at a bigger set of benchmarks; it seems that right now the sweet spot for a general instruction set architecture is 16-bit wide fixed-width instructions with a 32-bit risc like register and memory architecture, much like the thumb and thumb-2 ISAs. But it goes almost without saying that the msp430 ISA is exceptionally well designed, especially when considering it's relative age. (The interesting thing is that Samek's article benchmarks the PIC18 which is far better suited for the C language than the older PIC16 architecture… )

By: Nigel Jones

Nigel Jones — Fri, 08 Jan 2010 02:19:15 +0000

Hi Greg:Hardware abstraction has been the holy grail of low level embedded systems for a long time now. My gut feel is that it isn't going to happen (at least at the 8 bit level). However, we'll probably get close if and when the Cortex architecture consumes the entire embedded space. Personally as much as I can see the economic benefits of achieving this, I rather like the different personalities (quirks) of the various processor families. So if this does come about, I think I'll be a little bit sad.

By: Nigel Jones

Nigel Jones — Fri, 08 Jan 2010 02:15:25 +0000

You are quite right about the volume issue Anders. If you read this post http://www.embeddedgurus.net/state-space/2009/03/insects-of-computer-world.html by Miro Samek you'll get another point of view on the PIC. As for whether the PIC was the right choice for an ABS system, my sense is that it was a poor choice.

By: GregK

GregK — Thu, 07 Jan 2010 14:00:20 +0000

HiNice point Nigel.Apart of topic why we do not us high level of abstraction when interfacing with hardware (using RTOS or not)? If so we can get rid of of problems with changing architecture, upgrade hardware etc. However I do not know if 8bit's PIC allow on high level abstraction, what I am reading is not. Mayby this is reason why do not use 8bit's PICs.

By: Anders

Anders — Thu, 07 Jan 2010 11:58:18 +0000

Hi Nigel,Your post on hardware costs was very interesting, as always, and it is always refreshing to see this kind of arithmetics worked out. I think your numbers for breakeven are very valid for a small to medium sized production series. But I think it can change dramatically if the intended production volume is large or huge.We were once involved in a ABS braking project for a German automotive OEM. They chose a PIC16 over another 8-bit CPU mainly for cost reasons. Considering the production volumes for German car manufacturers in general and the number of embedded CPU:s in a modern car in particular I can really understand why they went for the PIC. But I'm not 100% sure that it was a sensible choice from a technical point of view…

By: Gauthier

Gauthier — Sat, 02 Jan 2010 14:06:25 +0000

There are also other ARM chips than AVR, I am not sure which are comparable to the chips you chose, but these look cheap:http://search.digikey.com/scripts/DkSearch/dksus.dll?Cat=2556109&k=cortex%20m0Which part would you say matches the PIC16F1936, and how much does it cost?