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Stellaris® ARM® Microcontrollers
Stellaris® ARM® LM3S Microcontrollers Forum
PCB Layout Guidlines for Ethernet?
The full schematic for the EKB-LM3S6965 eval kit is actually in the user manual. As far as I can tell, this board contains everything on your list with the exception of the I2C RTC module but the I2C is not used on the board so it should be very straightforward to add it yourself.If you want to download the manual, you can find it on this page. It's also on the CD that comes with the 6965 board.Please post a reply if there is anything else you need.
TI - Eric HewingWe have an application note planned for board layout recommendations. When it is ready, I will post a message indicating it can be downloaded.
I figured after 2.5 years this would be done. Is there an app note?
When it comes to routing differential eth lines standard rules apply (short tracks, continious return path and controlled impedances)
for a standard 1.6mm FR4 four layer pcb an adequate trace width of 0.22mm with 0.2mm spacing will result in
approximate Zdiff of 100 (5-10% tolerances depending on your manufacturer) for a differential microstrip. What
I usually do is to make a rough estimate of the single ended impedance of the track and use it to make a plot
of resulting differential impedance versus track separation, then I pick a width space ratio that looks sane. After the
layout is done and I'm about to send my odb/gerbers into production I specify the parameters of the stackup and
impedances (frequency range as well), so the pcb manufacturer can refine my design (if necessary) since they know their
production capabilities much better, they also run an impedance test on the produced pcb to verify the target impedance.
Hope this helps.
Taking a look at the datasheet for any ethernet enabled uC tells you that the following Isolation transformers will work (and Jacks with magnetics):
■ Isolation Transformers– TDK TLA-6T103– TDK TLA-6T118– Bel-Fuse S558-5999-46– Halo TG22-3506ND– Halo TG110-S050– PCA EPF8023G– Pulse PE-68515– Valor ST6118– YCL 20PMT04■ Isolation transformers with integrated RJ45 connector– TDK TLA-6T704– Delta RJS-1A08T089A■ Isolation transformers with integrated RJ45 connector, LEDs and termination resistors– Pulse J0011D21B/E– Pulse J3011G21DNL
No App note still!! Wow! Great! More than 2 years gone.
Amazing! I just stumbled upon what looks like the appnote many people have been waiting for - AN01283 - System Design Guidelines for Stellaris Microcontrollers. Seems incredible that basic info like this is only now coming out.
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