LM3S9B81 Datasheet, PDF (812/1155 Pages) Texas Instruments – Stellaris® LM3S9B81 Microcontroller

Ethernet Controller
//
if(Ethernet Energy Detected)
{
Reset Energy Detect Timer
if(New Energy Detect)
{
Reset Link Detect Timer
}
}
//
// If the Energy or Link Detect timer has expired, toggle the MDI/MDI-X
// mode. Typically, the Energy Detect Timer would be ~62ms, while the
// Link Detect Timer would be ~2s
//
if((Energy Detect Timer Expired) or
(Link Detect Timer Expired))
{
Reset Energy Detect Timer
if(Random Event)
{
Reset Link Detect Timer
Toggle MDI/MDI-X Mode
}
}
}
//
// Here, if an Ethernet Link has been detected, simply reset the timers
// for the next time around.
//
else
{
Reset Link Detect Timer
Reset Energy Detect Timer
}
19.3.3.5 Power Management
The PHY has two power-saving modes:
■ Power-Down
■ Energy Detect Power-Down
Power-down mode is activated by setting the PWRDN bit in the MR0 register. When the PHY is in
power-down mode, it consumes minimum power. When the PWRDN bit is cleared, the PHY powers
up and is automatically reset.
The energy detect power-down mode is activated by setting the EDPD bit in the MR17 register. In
this mode of operation, when no energy is present on the line, the PHY is powered down, except
for the managmenet interface, the SQUELCH circuit and the ENERGYON logic. The ENERGYON
812
June 29, 2010
Texas Instruments-Advance Information