hi friends,
I am doing one project and i am using rcm3720 core modules. My probleme is some of the modules suddenly not working and when observe them the link led of ethernet module is contiusly glowing right from powering up the module. I dont understand why it is happening . I have checked the power it is 4.6 volts one the board. Rabbit module stopped running. When i debugged the module i found that only when i am trying to interface with ethernet iface the module is not working. Other peripherals like serial port, serial flash are running fine.
Can any one give me a guess why it is happing. Its very urgent because project was a live one.
Sounds like you may have a hardware issue, either on or off the board. I am assuming you are using a standard development board for the RCM3720. If you are using your own design, then I may be off track as I do not know your design. The dev. board has a power supply that should maintain the 5 volt line within 4%. The 4.6 volts you mentioned is outside that range. Here is a link to the data sheet on the regulator, we use a LM2575-5.0 regulator. The second link is to the dev. board schematic.
http://www.national.com/ds.cgi/LM/LM1575.pdf
http://www.rabbitsemiconductor.com/documentation/schemat/090-0199.pdf
I would disconnect all external connections from the board. Check that your power supply is supplying more than 8 volts then attach power. Check the voltage again and see if it’s much closer to 5 volts. If so, you have something affecting the board. If not, you may have some blown components on the dev. board or core module. Assuming you see the voltage rise, connect the other external connectors one by one (power down if needed, then power back up). Check the voltage after attaching each one and see if it has dropped. This should point out which connection is pulling down the power supply. Hope this helps.