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OMAP-L138: UART Electrical Data/Timing spec.

Hitoshi Sugawara
Mastermind 19960 points
Part Number: OMAP-L138

Hi Champs,

Could you please let me know the main factor for the UART spec. as follows:

1) Table 6-90. Timing Requirements for UART Receive
     It shows 0.96U ns (min) and 1.05U ns (max).
     I think the majority of the factor for the variation is caused by the Baud Rate with Divisor Value setting.

2) Table 6-91. Switching Characteristics Over Recommended Operating Conditions for UARTx Transmit
    It shows U -2 ns (min) and U +2 ns (max).
     It think this is caused by the variation for each device.

Thank you very much in advance for the factor of the tolerance.

Best regards,
Hitoshi

  • 0
    TI__Mastermind 19960 points

    Hi Champs,

    I would very appreciate if someone reply for the questions.
    Our customer has another question as follows:

    "Table 6-90. Timing Requirements for UART Receive" in the datasheet.
     It shows 0.96U ns (min) and 1.05U ns (max).

    Does this mean OMAP-L138 can receive the UART data even though it is 0.96U or 1.05U ns?

    Thank you for your kind help.
    Best regards,
    Hitoshi

  • 0
    TI__Genius 9190 points

    Hitoshi Sugawara said:
    1) Table 6-90. Timing Requirements for UART Receive
         It shows 0.96U ns (min) and 1.05U ns (max).
         I think the majority of the factor for the variation is caused by the Baud Rate with Divisor Value setting.

    Correct, this just give the min and max duration of the pulse of the start and data bits that the device is guaranteed to be able to receive.

    Hitoshi Sugawara said:
    2) Table 6-91. Switching Characteristics Over Recommended Operating Conditions for UARTx Transmit
        It shows U -2 ns (min) and U +2 ns (max).
         It think this is caused by the variation for each device.

    Correct, this is the minimum and maximum time of the output pulse that is guaranteed.  

  • 0 in reply to Hitoshi Sugawara
    TI__Genius 9190 points

    Hitoshi Sugawara said:
    "Table 6-90. Timing Requirements for UART Receive" in the datasheet.
     It shows 0.96U ns (min) and 1.05U ns (max).

    Does this mean OMAP-L138 can receive the UART data even though it is 0.96U or 1.05U ns?

    Yes, this is the min/max requirements for the device to be guaranteed to latch the data properly.  

  • 0 in reply to Jeff Culverhouse
    TI__Mastermind 19960 points

    Hi Jeff,

    Thank you so much for your kind clarification.
    I understood well.

    Best regards,
    Hitoshi