Hello from France

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octal
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Location: Argenteuil - France

Hello from France

Postby octal » Fri Jan 28, 2011 5:59 pm

Hello,
I'm ahmed, from France.
One year ago, I was playing with Propeller chip, and I was trying to check all websites related to projects built using it.
On one blog, I found a comment saying that it's better to use XMOS like chips because they have more MIPS.
So I googled quickly on XMOS, and found the website, the video, dev tools, doc ...
I installed dev tools and does my first tests using the simulator!!!
When the guy who wrote the comment talked about MIPS as main difference, I personally found that the determinisme of XMOS was by far the main diff from Propeller. With XMOS, I can time exactly my outputs without having to use asm (like on propeller)....
1 week later I bought my dev kit and started devs!!! This WAS THE CHIP I always needed: the speed and flexibility and determinisme of FPGA, with an MCU core and a C like language for developments!
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leon_heller
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Postby leon_heller » Fri Jan 28, 2011 6:18 pm

Welcome to the forum!

I'm largely responsible for introducing Propeller users to the benefits of using XMOS, I mentioned the devices on the Parallax forum when they first became available.

A friend of mine who works at ESIEE, near Paris, is organising a competition between two groups of students working on the same project, one group will be using the embedded Java system favoured at the school and the other group will be using XMOS kit. XMOS gave him $250 worth of hardware under their university scheme.
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octal
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Postby octal » Sat Jan 29, 2011 4:07 pm

Hello Leon,
I saw all your posts about xmos on the parallax forums ;)
Propeller is nice for hobbists because of the DIP packaged version. This makes things easier for prototyping for hobbist. Propeller is nice mainly because of the counters modules and the video generator. You can do a lot with them without understanding anything to video frames, and using spin objects you can got your system working quickly.
The problem is that all that work within the magic black box composed by SPIN and signal generator. If you want to do anything deterministic, you need to go back to assembly. Memory management is strange (understandable, but not as clean as on XMOS). Each (asm) instructions is about 4 cycles, which means that your system is really a lot slower than basic XMOS L1 chip. and with all that, propeller lacks any protection system, and parallax team is conveinced that there is no need to protection system as any protection system is hackable. This alter a lot the development of professionnal tools based on Propeller and keep it usable only as a peripheral chip, as no serious/intelligent company would put its firmware open on a commercial product.
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leon_heller
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Postby leon_heller » Sat Jan 29, 2011 5:28 pm

Of course, the Propeller II will address a lot of those issues, including code protection, but it will still have to be programmed in assembler to get deterministic operation.

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