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Original question:

DP83TC811EVM: DP83TC811EVM

DP83TC811EVM: MDIO pin configuration inquiry for DP83TC811EVM

Kenny Li
Prodigy 10 points
Part Number: DP83TC811EVM
Other Parts Discussed in Thread: MSP430F5529,

Hi,

From the block diagram of DP83TC811EVM, the TI micro "MSP430F5529" has been used as to "USB-to-MDIO" communication, so as to support the read/write of Auto Ethernet PHY register.

However, to further look at the schematics about the pin connections of this TI micro which used to configure as MDIO and MDC pins. It is using pin 46 as MDC pin which pin 47 as MDIO pin.

In this way, how to do the GPIO configuration in the source code for this two pins? Are they both configured as SPI port interface? (As pin 46 is SPI's SIMO pin, pin 47 is SPI's SOMI pin, and pin 48 (not connected) is the SPI clock pin).

  • 0
    TI__Expert 4720 points

    Hello Kenny, 

    There are many differnent protocols used for data transfer between microcontroller and PHY. The one we use and the most common one is hte Management Data Input/Output (MDIO), also known as Serial Management Interface (SMI). This is a two pin interface hence 2 pins MDC and MDIO. Management data clock (MDC) and management data input/output (MDIO). 

    SPI port interface pins will be different from MDIO as the protocols are different. 

    Regards,

    Avtar 

  • 0 in reply to Avtar Dhaliwal
    Prodigy 10 points

    Hello Avtar,

    Thank you for your quick reply, really appreciate it.

    I am still a bit confused of how to configure these MDIO and MDC pins. As I checked in the TI micro "MSP430F5529" datasheet, pin 46 and pin 47 can both be configured as only GPIO/SPI/I2C pins. I cannot see pin 46 and pin 47 could be configured as MDIO/MDC pins from datasheet. 

    Is that mean it is not necessary to use pin 46/47 as MDIO/MDC pins? It could use normal GPIO pins to configured as MDIO/MDC pins? Or those pin 46 and pin 47 are really serial management interface (SMI) pins, just not mentioned in datasheet?

  • 0 in reply to Kenny Li
    TI__Expert 4720 points

    Hello Kenny, 

    These pins can be used for a variety of purposes. In our purpose as MDC and MDIO. For further questions on the MDP430 side however I would recommend reaching out to their team as they have more knowledge on pins and capabilities.

    Regards,

    Avtar