RE: Can -- Sampling time point of -- 87.5%

John,

I'm sorry I can't help you.  I really don't understand what you are asking
for.  There are numerous calculators out there for CAN bus sampling points
and bus lengths. The sample point is chosen as an optimal point where the
signal is still 'healthy' on a given bus.  Choose cable with the wrong
impedance, choose to operate at the maximum length for a specific bit
rate, choose cable with a high capacitance, choose drivers that are
non-optimal for CAN, use opto-isolators between the CAN device and the
driver... all those affect what sample point you choose.

As I understood your question you wanted to know how to get an 87.5%
sample point. The answer was simple.  Sample at T_SEG 14 when there are 16
T_SEG per bit.

It's a standard GIGO (from the 1970's  -- Garbage In, Garbage Out).
There's no such thing as a dumb question but you do have to ask
specifically what you want or you will get either nothing or answers that
don't make any sense.

John Dammeyer



"ELS! The Solution"
Automation Artisans Inc.
http://www.autoartisans.com/ELS/
Ph. 1 250 544 4950


-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of John
cliffer
Sent: Tuesday, December 04, 2012 11:20 PM
To: CANLIST
Subject: [CANLIST] Can -- Sampling time point of -- 87.5%


>> It's simple math really.



That is fine john which everyone knows .... means we have to repeatedly
perform the calculation given in AN1798 doc to decide which fits best for
your sample point.


And when adjusting timings of segment to achieve our sample point. This
may led to reduce in maximum length of cable use between farthest node on
BUS.

//John



On Wed, Dec 5, 2012 at 12:24 PM, John Dammeyer <[email protected]>
wrote:


It's simple math really.