If register access is not readily available in the application, USB-2-MDIO GUI is available from TI and can be used with an MSP430 Launchpad. The GUI supports reading and writing registers as well as running script files. The GUI can be used with the DP83TC812 and all other TI Ethernet PHYs. The USB-2-MDIO User's Guide and GUI are available for download here.

Figure 4-14 USB-2-MDIO GUI

Figure 4-15 MSP430 LaunchPad

Below is an example script that can also be found in the USB-2-MDIO GUI in the Help menu:

// This is how you make a comment. All scripts must start with 'begin' 
begin
// To read a register, all you need to do is put down the 4 digit
// HEX value of the registers (from 0000 to FFFF) 
// Example to read registers 0001, 000A, and 0017 
0001
000A
0017
// To write a register, all you need to do is put down the 4 digit 
// HEX value of the register (from 0000 to FFFF) followed by the 
// HEX you desire to configure the register to (from 0000 to FFFF) 
// Example to write 2100 to register 0000 and
// Example to write 0110 to register 0016 
0000 2100
0016 0110
// You must end the script by adding 'end' once you are finished
end

The Serial Management Interface defined by IEEE 802.3 is a single master bus. The MDC clock is generated by the bus master, typically an Ethernet MAC. To use the USB-2-MDIO GUI, connections must be made directly between the MSP430™ Launchpad and the DP83TC812 MDIO and MDC pins.

• Launchpad Pin 4.2 → PHY's MDIO Pin

• Launchpad Pin 4.1 → PHY's MDC Pin