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AM2434: EEPROM WP GPIO

Mari Tsunoda
Expert 5726 points
Part Number: AM2434

Tool/software:

Hi Team,

My customer wants to use IO pins to unlock the write protect on their EEPROM only in the situation that they write to it from the AM243x. 

Is there any restriction to which IO pins they can use to access write protect pin?

Best regards,

Mari Tsunoda

  • 0
    TI__Expert 5726 points

    Also, is there some reference schematic for this?

  • 0 in reply to Mari Tsunoda
    TI__Mastermind 48758 points

    Hi Mari,

    Mari Tsunoda said:
    Also, is there some reference schematic for this?

    Which schematic details are you referring to? Is it EVM schematics or EEPROM schematics?

    Regards,

    Tushar

  • 0
    TI__Mastermind 48758 points

    Hi Mari,

    Mari Tsunoda said:
    Is there any restriction to which IO pins they can use to access write protect pin?

    Please refer section 7.5 Write Protection of the EEPROM-Data-Sheet for details.

    Regards,

    Tushar

  • 0 in reply to Tushar Thakur
    TI__Expert 5726 points

    Hi Tushar,

    Sorry, my original question was not that clear. 

    I think the implementation for the board ID EEPROM on the EVM has it such that WP is tied to 3.3V so it is held to HIGH and WP is always enforced.

    However, they want to control the EEPROM using a GPIO signal from AM2434 instead so that they can write to it from AM2434. 

    Is this ok to implement? And in this case, is there any GPIO pin that are off limits?

    Also, is there any schematic that shows the implementation mentioned? (I checked the LP and EVM and this does not seem to be the case)

    Best regards,

    Mari Tsunoda

  • 0 in reply to Mari Tsunoda
    TI__Guru**** 189649 points

    Hello Mari Tsunoda

    Thank you.

    Pls Refer below the EEPROM WP explanation:

    Write-Protect (WP) The write-protect input, when connected to GND, allows normal write operations. When the WP pin is connected directly to VCC, all write operations to the protected memory are inhibited. If the pin is left floating, the WP pin will be internally pulled down to GND. However, due to capacitive coupling that may appear in customer applications, Microchip recommends always connecting the WP pin to a known state. When using a pull‑up resistor, Microchip recommends using 10 kΩ or less

    I do not expect any issue with using any of the IOs for WP control.

    Regards,

    Sreenivasa