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PGA305: EEPROM Access

Jourdan Stephane
Prodigy 30 points
Part Number: PGA305

Hi,

I am trying to dialog with PGA305 via I2C. My hardware interface is National Instrument NI USB-8451. I’m using I2CADDR = 0. My main problem is to read EEPROM registers (address 0x45).

If I write the value 0x03 @Address 0x40 & @ register 0x0C,  I can read the written value with success (0x03). Then I can read registers @ address 0x42 correctly but not  @ 0x45 (all value are set to 0).

Moreover, If I write 0 to BRDG_CTRL (address 0x42, register 0x46). The pin BRG+ should be 2.5 V referenced to BRG- but it is frozen to 0V. I tried also with the value 0x02 ,0x04 and 0x06 but without any success.

Is there anything to write in one register to read the EEPROM please?

Regards,

Bastien

  • +1
    TI__Mastermind 31655 points

    Hi Bastien,

    You should be able to read the EEPROM directly or by loading the data into the EEPROM cache and reading from those registers. Can you check to see if you are able to read from the EEPROM cache? You will need to write to the EEPROM_PAGE_ADDRESS register (0x88) to select a page, and it will load the 8 bytes from that page into the cache (0x80 - 0x87).

    I also recommend trying to program a value into the EEPROM then reading it back. Programming the EEPROM requires use of the cache and the EEPROM_CTRL register. You can refer to the EEPROM Programming Procedure section of the datasheet for detailed instructions on writing to the EEPROM. 

    Your trouble with the BRDG_CTRL seems to be different since it is part of the control and status register page. You are certain that you are able to read and write to other registers in the control and status register page (address 0x42)? The simplest way to test this is to enable the DAC output to the VOUT pin (set TEST_MUX_DAC_EN to 1 in the AMUX_CTRL register: 0x67), and to change the values in the DAC_REGx registers while monitoring the voltage at VOUT. You should be able to see the voltage change as you adjust the DAC value. All of this must be done will the PGA305 is in the reset state.

    One thing to note about the BRDG_CTRL is that the settings that are programmed in the control and status registers (address 0x42) will not be saved when the PGA305 is put into compensation mode. If you try to set the register and come out of reset, the value will be programmed back to whatever it is set as in the EEPROM BRDG_CTRL. 

    Regards,

    Scott

  • 0 in reply to Scott Cummins
    Prodigy 30 points

    Hi Scott,

    Thanks for your prompt & accurate reply.

    Regards

    Bastien