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Ethernet through RMII on STM3240G-EVAL, anyone?

Posted on October 02, 2012 at 13:04

Anybody using Ethernet on the STM3240G-EVAL board in RMII mode? I have tried and it was a challenge of sort:

- soldering the SMD 50MHz oscillator is quite impossible, given the cramped space (I don't quite understand why ST spared down a $1 part from a $350 board). I solved it through using a much smaller oscillator (2mm x 3mm ASE series of Abracon, instead of the ''original'' 5mm x 7mm), having ''extended'' its contacts to the PCB pads using short wires

- while the oscillator is located quite close to the PHY, the 50MHz clock (possibly the fastest signal on the board) is then routed through some 10 cm to the extension header, and back further 5 cm to the mcu. The performance was then, ehm, marginal (it sort of worked when loaded by a LA's probe). Had to cut the track to the extension header and reroute it the shortest possible way by a wire, which given the track width was quite a challenge too

Comments, please.


Jan Waclawek

#rmii #stm3240g-eval
Posted on October 02, 2012 at 19:15


or even:

...might have been more fun?

Posted on October 03, 2012 at 08:58

I wrote the original post in the hope it could help those who already have the STM32x0G-EVAL board and wish to use RMII. But for those who are  just planning to get a devboard, those Olimex boards look as an attractive alternative indeed.

Do you have first-hand experience with them, David? Or anybody else?