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Subject: 
Re: Brainstorms
Newsgroups: 
lugnet.robotics
Date: 
Tue, 13 Aug 2002 01:29:59 GMT
Viewed: 
985 times
  
In lugnet.robotics, Matt Lawrence <matt@technoronin.com> writes:
On Sun, 11 Aug 2002, Steve Baker wrote:

[snip Philips uC]

My biggest problem with I2C is addressing.  Each device needs
needs to have its address pins properly set.

Address pins?  What address pins?

I think the addressing problem can be solved with random numbers and some
serious bus scanning.  Failing that, burning a serial number into each
chip isn't that hard either.  It would still require quite a bit of bus
scanning, but even if the startup took several seconds, I don't see it as
a problem.

The I2C bus is not really designed to support a bus scan.
I'm not saying it can't be done, but I certainly haven't
figured out how to do it.  Until I see somebody who gives
an extremely detailed description of how they do it, I will
remain extremely skeptical.  No offense is intended here.

Converesly, the SPI bus has a separate chip select per package,
so a bus scan is much easier, although still quite difficult.

-Wayne



Message has 2 Replies:
  Re: Brainstorms
 
Matt Lawrence wrote: > I think the addressing problem can be solved with random numbers and some > serious bus scanning. Failing that, burning a serial number into each > chip isn't that hard either. It would still require quite a bit of bus > (...) (22 years ago, 13-Aug-02, to lugnet.robotics)
  Re: Brainstorms
 
(...) Since I had to support hot-pluggable devices on the bus (not my idea), I had to continually scan the bus. Unfortunately, that was several years ago and I don't remember all of the details. It took either a zero-length read or a zero-length (...) (22 years ago, 13-Aug-02, to lugnet.robotics)

Message is in Reply To:
  Re: Brainstorms
 
(...) I did a project with the Philips chips several years ago. I2C worked very well, the smallest chip I used was a 87C751. A little bit bigger than an 8-pin chip, but available in surface mount packages. Also, a friend of mine used a 751 as an I2C (...) (22 years ago, 12-Aug-02, to lugnet.robotics)

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