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LMK05318B: Device Start-Up Modes

x ly
Prodigy 20 points

Part Number: LMK05318B
Other Parts Discussed in Thread: LMK05318

Tool/software:

Hi community

I would like to ask about the specific process of device startup.According to the description in the datasheet, the LMK05318B has three startup modes, namely EEPROM+I2C, EEPROM+SPI and ROM+IC. When I select EEPROM+I2C, I assume that it first configures the register according to the internal EEPROM pre-set when it starts, and then scans the external device through I2C, If I2C is connected to an external EEPROM, it will reconfigure the register according to the firmware stored in the external EEPROM to determine the final output state. In the whole process, LMK05318 serves as the host to access the stored content of both the internal and external EEPROM,so, I would like to know whether my understanding is correct? If so, whether the same is true of EEPROM+SPI and ROM+I2C?

In addition, I have the following questions hope you can help answer:

1. Are there any restrictions on the device type of external storage firmware? Whether FLASH and EEPROM are supported
2. What is the difference between EEPROM+IC and ROM+I2C modes, and what is the difference in the scenarios applicable to these two modes

Best Regards,

  • 0
    TI__Genius 17025 points

    Hi X,

    1. "If I2C is connected to an external EEPROM, it will reconfigure the register according to the firmware stored in the external EEPROM to determine the final output state. In the whole process, LMK05318 serves as the host to access the stored content of both the internal and external EEPROM"
      1. The above statement is incorrect. The LMK05318B is always the peripheral device that needs an external host to send the I2C commands.
      2. At start-up, the internal EEPROM settings are automatically loaded into the register space of the LMK05318B. Once I2C communication becomes available (about 30 ms after PDN goes high), an external host is required to drive the I2C transactions.
      3. External EEPROM readback by LMK05318B is not supported.
      4. This is true for all start-up modes.
    2. As mentioned, external EEPROM/flash are not supported by the LMK05318B unless there is an external host device available to drive the interaction between the external EEPROM/flash and LMK05318B.
    3. The ROM pages are no longer recommended for customer use and will be removed from the datasheet. These contain fixed register configurations which are no longer suggested for use. In contrast, the EEPROM settings are not fixed and can be programmed up to 100 times by the user with the desired register configuration. It is recommended to program the EEPROM for applications that require start-up clocks and cannot perform in-system programming after start-up.

    Regards,

    Jennifer

  • 0
    Prodigy 20 points

    Thanks for your reply. There is another question. According to the second point above, when the host modifs the firmware stored in the external EEPROM/FLASH to LMK05318, is the modification permanent? Does the operation need to be repeated at the next startup

  • 0 in reply to x ly
    Intellectual 341 points

    No, the modification is not directly permanent.
    The i2c host controller can write to the LMK configuration registers. The registers are volatile and need reprogramming after power cycle. But once the LMK is programmed and functioning correct you can commit the registers to the LMK's internal eeprom to be loaded automatically after power cycle.

  • 0 in reply to Octo Halsema
    TI__Genius 17025 points

    Hi X,

    Octo is correct that the the active register space is volatile memory that return to a default state after each power on/off. If you want to avoid reprogramming each time at start-up, I recommend you program the internal LMK05318B EEPROM.

    Regards,

    Jennifer

  • 0 in reply to Jennifer Bernal
    Prodigy 20 points

    Hi Jennifer

    Thanks,Your response was very helpful,I read the programming instruction manual for LMK05318, so I have a new problem,Assuming that my device is operating in an environment full of interference, even the on-chip EEPROM is not reliable. In this case, I save the firmware through the off-chip reliable storage device and write it to the register of the LMK05318B through the external host at each restart, without using the on-chip EEPROM at all times. Is it feasible? If this works, I want to know if it takes effect immediately after each write to the register

    Regards

  • 0 in reply to x ly
    TI__Genius 17025 points

    Hi X,

    I will get back to you today or tomorrow.

    Regards,

    Jennifer

  • 0 in reply to Jennifer Bernal
    TI__Genius 17025 points

    Hi X,

    1. I'm confused on the comment about the LMK05318B internal EEPROM not being reliable. All of our devices are screened for faulty EEPROMs or other potential issues. These faulty devices are discarded prior to reaching a customer. In addition, each device is individually tested to make sure the datasheet specification is met.
    2. There is no way to bypass the internal LMK05318B EEPROM load at start-up. With that said, every LMK05318B device is preprogrammed with a default EEPROM configuration. This default EEPROM configuration sets the outputs to a disabled state. This means that while the external EEPROM programs the registers, the outputs remain disabled at start-up. You can set the last instruction of the programming to enable the outputs per your desired configuration. Additionally, you may configure the SYNC enables for each register and set SYNC =1 as the first instruction to bring all of the outputs to a disabled state, then set SYNC=0 as the last instruction to have all of the outputs come up at the same time.
    3. "If this works, I want to know if it takes effect immediately after each write to the register."
      1. What do you mean by "it takes effect"? What is "it"? The register writes are immediate. The speed of programming depends on the I2C/SPI rate.

    Regards,

    Jennifer