Hi
First let me start by describing the hardware that I am using. I am using the SMSC LAN91C111 ethernet MAC & PHY which is driven by the Renesas 7144F processor (16-bit interface). I am not using a EEPROM in conjunction with the SMSC device hence the EEPEN pin is tied low and the IOS0-2 pins are left floating. Furthermore RBIAS is tied via a 11K resistor to ground.
As the hardware stands at present, I am able to write and read data to the MAC correctly. This has been verified for all 4 reg banks of the MAC. What is strange is that I cannot seem to access the PHY in any way whatsoever. I am using the MGNT reg in bank 3 and clocking the data as described in the data sheet by starting with 32 1's etc etc.
Obvioulsy you cannot tell what is going on in the chip so I then set the SMSC to external PHY. By doing so, I was able to see the data being clocked correctly out on the MDO pin as well as the MCLK pin toggling. I then set the device to use the internal PHY once again but alas no luck! It just seems dead. The only data that I get is a series of: 0x0000
The data sheet doesn't mention what the maximum speed for communicating with the PHY is. Can anyone shed some light on this? Also, does anyone have any other suggestions for me to try as I am now starting to get desperate? I have looked at the SMSC trouble shooting FAQ and have ensured that all the bits are set/cleared correctly as recommended in order to solve this type of problem. Still no luck though.
Please help if you can!
Many thanks Ryan