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TPS929120-Q1: Access EEPROM while internal addressing

Mohamed Saleh1
Prodigy 90 points
Part Number: TPS929120-Q1
Other Parts Discussed in Thread: TPS929121-Q1

Hello,

Is there a way I can access the EEPROM programming while the chip is programmed previously for internal addressing and at the same time without using Ref pin to select the chip? 

Best Regards

  • 0
    TI__Genius 15776 points

    If there is only one device you can use the default internal address to access the E2PROM

    if there is more than 2 chip you should use external add pin.

  • 0 in reply to Frank Qiu
    Prodigy 90 points

    What if I have configured internal address as 0x00 and I need to access EEPROM of another chip configured as internal address as 0x0A.

    According to the datasheet, if I used the reference pin, I shall address the selected chip with address zero.

    But that will create a conflict on the bus because by selecting device address 0x0A with reference pin, it automatically changes its address to zero, while there is another chip with the same address

  • 0 in reply to Mohamed Saleh1
    TI__Genius 15776 points

    That's right. 

    So we recommend use address pin to set the device address because the default address is external address. The default external address is 0 due to the internal pull-down resistor of address pin.

    When you pull up the ref pin, that means use the internal address and the default internal address is 0. So there be a conflict if there are other device in  in the UART bus with external pin floating.

  • 0 in reply to Frank Qiu
    Prodigy 90 points

    Okay, thank you. 

    A few more questions regarding this topic, in the datasheet, it says that it is recommended to use the address pins if I have 8 or less devices on the Fexwire interface. Does that mean I should use the internal addressing in case I have more than 8 devices? 

    What is the reason behind this recommendation? 

    If I used the internal addressing register and I have 16 devices on the network, will that create an issue besides the previously mentioned EERPOM accessing?

    When you say the default address is the external address, Does that mean if I have the external address pins configured, for example address 0x1, and I configured the address to internal addressing and used reference pin to select the device for EEPROM accessing, the default address will be 0x00 or 0x01.

    According to my understanding from the datasheet, the chip will ignore both address pins and internal addressing in case the Ref pin is pulled high. 

  • 0 in reply to Mohamed Saleh1
    TI__Genius 15776 points

    A few more questions regarding this topic, in the datasheet, it says that it is recommended to use the address pins if I have 8 or less devices on the Fexwire interface. Does that mean I should use the internal addressing in case I have more than 8 devices? What is the reason behind this recommendation? 

    A:Whether the device use external or internal address is based on the EEP_INTADDR and it's default value is 0(use EEP_DEVADDR[3] code together with external inputs on ADDR2,ADDR1 and ADDR0). the default value of EEP_INTADDR and EEP_DEVADDR[3] is both 0. So when device is more than 8, you should use EEP_DEVADDR[3] to distinguish the address lager than 8 for example 0001 and 1001 which the bold is EEP_DEVADDR[3] and 001 is external address.

    If I used the internal addressing register and I have 16 devices on the network, will that create an issue besides the previously mentioned EERPOM accessing?

    A: We have another solution for this case, we will release a device named TPS929121-Q1 which the EEP_DEVADDR[3]'s default value is 1. That can easily solve the issue you ask.

    According to my understanding from the datasheet, the chip will ignore both address pins and internal addressing in case the Ref pin is pulled high.

    A: When you first burn the E2PROM and pull up the ref pin, the device will use internal address, if it ignore the internal addressing how could we build the communication.