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Original question:

PROCESSOR-SDK-OMAPL138: Interfacing MCBSP0 of LCDKOMAPL138 with another C6000 DSP

PROCESSOR-SDK-OMAPL138: Mcbsp configuration as UART in LCDKOMAPL138

Waseem Ajmal
Intellectual 310 points
Part Number: PROCESSOR-SDK-OMAPL138
Other Parts Discussed in Thread: OMAPL138, OMAP-L138

I want to configure MCBSP0 of LCDKOMAPL138 to work as Uart. I have followed Application Report SPRA633C which show that how MCBSP of C6000 devices can be used as UART. However after adding these configurations, I am unable to observe any data to/from UART.

Please guide me if it is possible for me to configure MCBSP of OMAPL138 to work as UART.

Regards,

Waseem Ajmal.

  • 0
    Intellectual 310 points

    This is so unfair that consultants at e2e doesnot reply to the asked questions. or mostly reply with we donot have support in this or that.. please reply to my questions as I need to get it done on proiority basis. MY project is pending due to this. 

    Regards,

  • 0
    TI__Mastermind 29270 points

    Hi,

    The OMAP-L138 has native UART ports available if you do not want to use McBSP as UART.

    On LCDK J3 USB port gets UART2 (UART VCP)
    UART1 is also available on header J15 if you populate R206 and R209.
    UART0 can also be routed to header J15 if you remove R172 and R173, and populate R218 and R219.

    McBSP can also be used as a UART with the help of software.
    Are you trying to implement Serial Port Mode with software from Appendix A.1 in SPRA633C?
    With that mode, the below McBSP pins are wired to the UART device as shown in Figure 2. UART Connection - Serial Port Implementation.

    UART_TX connected to both
    MCBSP0_DR0 on AXR2/MII_TXD2 and
    MCBSP0_FSR0 on AXR4/MII_COL

    UART_RX connected to
    MCBSP0_DX0 on AXR1/MII_TXD1

    If not removing U23 on the LCDK, at least hold it in reset with PHP_RSTn and hope that it releases these pins with high impedance.

    The McBSP configuration needs to be set exactly as described in this appnote.

    It might be easier to start by processing the UART data word-by-word instead of in blocks. To get block processing to work will require the DMA and interrupts.

    Once you get the software to compile and execute, try to connect an oscilloscope to the DX0 to see if it at least toggles. Then look for the Start bit followed by binary bits of each data byte.

    On the receive side, send some known data and compare against the data received from McBSP receiver.

    Regards,
    Mark

  • 0 in reply to Mark Mckeown
    Intellectual 310 points

    Hi I am following SPRA633C for mcbsp configuration as uart in OMAPL138. I have verified my hardware connections already but I am unable to send / receive data via TTL when used with mcbsp interface of OMAPL138. If you have any example of the code in which MCBSP of OMAPL138 has been configured as uart and its operational, then please do share. As I am having issues in this since last two weeks.

    Regards,