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MCT8316A: Read and write RAM

Cherry Zhou
Mastermind 22235 points
Part Number: MCT8316A

Hi team,

Here's an issue from the customer may need your help:

When reading and writing EEPROM, LSB Byte first according to user guide, the customer would like to know if reading or writing RAM registers, is it the same(LSB Byte first)?

As shown above, E6 is a RAM register, and when performing a data write in 1, the order in which 0x40 00 00 is sent is 40 00 00 00 Or 00 00 00 40?

Could you help check this case? Thanks.

Best Regards,

Cherry

  • 0
    TI__Mastermind 26046 points

    Hi Cherry, 

    We will get you a reply on Monday.

    Thanks,
    Aaron

  • +1
    TI__Genius 9220 points

    Hi Cherry,

    The byte order is the same when reading or writing to RAM or EEPROM's shadow registers. LSB first means that 0x40000000 is sent in the order of 0x00 0x00 0x00 0x40.

    Regards,
    Eric C.

  • 0 in reply to Eric Chen
    TI__Mastermind 22235 points

    Hi Eric C,

    Here's one more question: 

    Reading EEPROM requires copying to buffer and waiting 100 ms before reading. In the case of the 8316 ram register, is it possible to directly send the control word read? No additional replication and wait is required. 

    Thanks and regards,

    Cherry

  • +1 in reply to Cherry Zhou
    TI__Genius 9220 points

    Hi Cherry,

    Yes, at any time, you can directly read from both the RAM registers and the shadow registers (copy of EEPROM) without copying the content from the EEPROM into the shadow register. The values in the shadow registers are what get used by the motor control algorithm during operation. And the shadow registers actually resides in the RAM part of the device memory. The EEPROM memory is simply used for non-volatile storage. 

    On power-up, the MCT8316A automatically copies the content of the EEPROM into its shadow registers. Afterwards, the EEPROM_READ procedure is used to manually copy the EEPROM content into the shadow register, if the shadow register has been modified, and the user wish to re-load the settings stored in EEPROM into the shadow register.

    Regards,
    Eric C.