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TL16C754C, not able to recive the data

Pra
Genius 11085 points
Other Parts Discussed in Thread: TL16C754C

Hi Team,

Please give us your advice on the below customer inquiry;

We are using TL16C754C QUAD UART, if we do continous data transfer, not able to recive the data from the device(chip). the LSR bit0 not getting high, some times we read 0xFF on data bus. we are not using interrupt pins.

Regards,

Prasanna Dayala.

  • 0
    TI__Expert 5230 points

    What are the baud rates of the two nodes? Are they different?

    What is the word length? 8N1?

    What crystal or oscillator is used on each node

    Are you using FIFO mode or non-FIFO mode?

    Can you send code showing how you initialize and set up the TL16C754C device?

     

    Best Regards,

    Joe

  • 0 in reply to Joe Fockler
    TI__Genius 11085 points

    Hi Joe,

    1. Our baud rate is 9600 for TX and RX, its 8N1 only

    2.1.8432MHz crystal we are using, tested FIFO & non FIFO modes also

    The problem is:
       After the initialization the communication getting started, after some time the data is not receiving in the FIFO. the LSR [0] is always 0.   the same problem appearing in all the UART channels. we have tried in non FIFO mode also.
       Tested on External loop back mode
       UART A : Tx <-> UART A :Rx
       UART B : Tx  -> UART C: Rx
       UART C: Tx  -> UART B: Rx

    Initialization sequence
                               (A2 A1 A0) = (Value)
    QUAD_UART_LCR        (3)  = 0x80    -->DLL_DLH_ENABLE;
    QUAD_UART_DLL        (0)  = 0x0C    --> 0x000C
    QUAD_UART_DLH        (1)  = 0x00
    QUAD_UART_LCR        (3)   = 0x00    --> ENABLE_PRIMARY_REG
    QUAD_UART_LCR        (3)  = 0x03     --> 8N1
    QUAD_UART_IIR_FCR (2)  = 0x00     --> Disable FIFO
    QUAD_UART_IER          (1)   = 0x00    --> DISABLE_ALL_INTERRUPT

    Here with I have attached the initialization for the QUAD UART for your reference.

    Regards,

    Prasanna Dayala.

    TL16CP754C.zip
  • 0 in reply to Pra
    TI__Genius 11085 points

    Hi Joe,

    Any updates on the customer inquiry.

    Regards,

    Prasanna Dayala.

  • 0 in reply to Pra
    TI__Expert 5230 points

    Please ask the customer to return the failing devices for Failure Analysis (FA).  Our lab bench test (TL16C754CPM (PM package)) does not show this failure.

    What is the date code on the top of the failing devices?

    Regards,

    Joe

  • 0 in reply to Joe Fockler
    TI__Expert 5230 points

    Is the RXRDY# signal monitored to indicate when a character is received?

    I don't see any problems with the initialization code but it might be useful to reset the FIFOs to a known state and clear the FIFO pointer, even though DMA mode 0 is used (see red text below)

    Initialization sequence
                                             (A2 A1 A0) = (Value)
    QUAD_UART_LCR        (3)  = 0x80    -->DLL_DLH_ENABLE;
    QUAD_UART_DLL        (0)  = 0x0C    --> 0x000C
    QUAD_UART_DLH        (1)  = 0x00
    QUAD_UART_LCR        (3)  = 0x00    --> ENABLE_PRIMARY_REG
    QUAD_UART_LCR        (3)  = 0x03    --> 8N1
    QUAD_UART_LCR        (2)  = 0x04    -->  RESET TX and RX FIFOs
    QUAD_UART_IIR_FCR    (2)  = 0x00    --> Disable FIFO and select DMA Mode 0
    QUAD_UART_IER        (1)   = 0x00    --> DISABLE_ALL_INTERRUPT

    Can the customer provide a oscilloscope trace of the data bus and TX and RX lines from a Tek MSO4104 or a LeCroy scope?

    Best Regards,
    Joe