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Problem With Ethernet RMII Module Infinite SoftwareReset Loop

jones.david
Associate II
Posted on September 19, 2015 at 15:27

Hello to All

I am Working on a RMII Module With DP83848v.I use Stm32f4xg Eval Board Schematic to Design this board.(you can download it in st site that you knew it better than me)

i noticed that St design Ethernet that can be used as MII and RMII So i copied this Schematic to my Project(with just chnaging resistor as single resistor not Package Resistor).

I assembled it in RMII Config and found that it's not Working

i compare it to

http://www.waveshare.com/w/upload/3/31/DP83848-Ethernet-Board-Schematic.pdf

from waveshare and found that pin39 in phy is connected to RX_DV_MII/CRS_DV_RMII Which is Wrong i think because in RMII CRS_DV Located in pin40.(please tell me if i'm wrong)so i cut tracks on my board and repair my board just like Waveshare's Board.

i connect my ethernet module to a Stm32f429IIT Board and Connect Pins like below

PA1--->MII_RX_CLK/RMII_REF_CLK

PA2--->MII_MDIO

PA7--->MII_CRS

PC1--->MII_MDC

PC4--->MII_RXD0

PC5--->MII_RXD1

PG11--->MII_TXEN

PG13--->MII_TXD0

PG14--->MII_TXD1

i test module with

https://github.com/MaJerle/stm32f429/tree/master/52-STM32F429_ETHERNET_SERVER

this project is by default RMII and i test it in another project that worked correctly and i just checked pin Configuration in GPIO_Config method.

i executed project and in debug mode i see it is in an indefinite loop software reset. i checked 50MHZ MAC to phy oscilator in both end and they are OK.

i replaced 10MHZ oscilator with a 8MHZ crystal(with changing programm)

i used mxcube and the same result occured.

i guess that long distance between ethernet module and MCU module causes problem but i'm not sure about it because 50MHZ is not a high frequency.

#rmii #stm32f429
1 REPLY 1
jones.david
Associate II
Posted on September 20, 2015 at 13:32

thanks for kindness reply b:)) problem was sth relate to stm32f429 IC. i dont know why but it solves when i replace it with another chip

in some ic one peripheral is broken .i had a 407 with usb on GPIOA broken(i replaced IC so that usb worked)