On Thu, Nov 6, 2008 at 11:03 PM, Walter Banks <walter@bytecraft.com> wrote:
>> And even if you are right, the ability of the enhanced PIC16F
>> has already been available in PIC18F for years. And none of
>> the things come close to what you think have come into reality.
>
> True but there is a lot of work now on distributed processing and
> on the ISO61131 and ISO61499 standards. As an alternative to
> RTOS's in small embedded systems event driven programming
> works well.

Depending on what you do, this distributed unit will still often
require more processing power than an enhanced PIC16F or
lower end PIC18F. In fact, I've seen this kind of distributed
unit (support limited function blocks) mostly using lower-end
32bit MCU like ARM7 level. But if you only want to use
a dedicated function, it should be feasible.

> I have done a lot of work in tools support for automotive engine
> controllers. Most of them use a multiprocessor based event
> system consisting of a powerPC sized host CPU and two
> I/O event driven processors. The operation is surprisingly similar to
> ISO/IEC 61499. There is no RTOS in the host CPU.

Interesting. I always think Automotive has a lot similarity
with Automation. For example, CAN is widely used in
both. If FlexRay becomes cheaper, it will find good use
in the factory automation market as well due to the
advantages over Ethernet based protocol (deterministic).
The biggest disadvantages about CAN are as following.
1) Speed: 1M can limit the bandwidth
2) Packet size and fragmentation : can be a bigger disadvantage
than the speed issue
3) Non-deterministic.

TTP/ByteFlight/FlexRay seem to be trying to solve the
problem of CAN.

Xiaofan
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