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CCS/TMS570LS3137: N2HET emu sci problem. There is some changes in het ram/instruction values, but there is no transmission on pin

user6300884
Prodigy 140 points
Part Number: TMS570LS3137
Other Parts Discussed in Thread: TMS570LS0432, HALCOGEN

Tool/software: Code Composer Studio

Hello,

I am struggling to use n2het pin of tms570ls31usb as sci.

n2het[6]-----rx

n2het[13]---tx,

I used the code inside attached file.  The only difference between the code I used and the code in attached file is change of pins inside assembly code .When I examine the values of data of het ram-instructions during transmitting a letter, I can see the changes. Especially when I try to send a letter on polling mode, instruction[4].data is changing. But there is no transmission  on the tx pin / n2het[13]. Is it enough to access and change some values in the het ram for transmission?

I have also heard that htu is necessary for transmission between het ram and main ram. But this example does not use the htu for the transmission, only make some changes in het ram.If you have any idea, please share with me. Thanks in advance.

7444.TMS570LS04_HET_EMU_SCI.zip

  • 0
    TI__Guru**** 196306 points

    Hello,

    On TMS570LS3137ZWT package, the N2HET1[6] and N2HET1[13] are multiplexed with SCI_RX and SCI_TX. Have you configured the pinmux correctly? Why do you those two pins as emulated SCI pins? If those two pins are used as N2HET signals (emulated SCI),they can not be used for SCI functionality (SCI_TX, SCI_RX).

    Does the emulated SCI work without the modification? Do you change the SCI baudrate configuration since two devices may be configured to run at different system clock? The maximum system clock of TMS570LS0432 is 80MHz, but 180MHz for LS3137ZWT (160 for PGE package).

    Yes, you can use HTU to transfer data between NHET RAM and MCU SRAM. Please find the HTU example code in the following sppnote:

    https://www.ti.com/lit/an/spna217/spna217.pdf

  • 0 in reply to QJ Wang
    Prodigy 140 points

    Thanks for your response.

    Yes, I paid attention pinmux settings. When I selected the sci_rx and sci_tx, there was no conflict in N2het1[6] and n2het[13] pins.

    The card that I used is not hdk, it is TMS570LS31USB and I must use the n2het pin as sci. I thought that using advanced n2het settings ,I can close n2het functionality of these pins and use it them as normal sci. 

    Do you think that the code that I attached in my previous post is enough? Should I make any change without changing the pins in assembly code?(because I can observe the change of instructions in het ram but there is no transmission on tx pin.) Is this code using htu etc. which provides transmission from nhet ram to tx pin background?

  • 0 in reply to user6300884
    TI__Guru**** 196306 points

    Yes, you don't need to change the code, but you have to adjust the VCLK2 and LRP to get your baudrate.

    Please refer to the appnote: UART Implementation Using the N2HET 

  • 0 in reply to QJ Wang
    Prodigy 140 points

    Thanks, transmission over het pin is performing. (The real problem was selecting sci_tx pin instead of het1[6] in pinmux.)

    But the new problem is reception . I only control data of 25. instruction in HET RAM to arrive data coming from het rx pin n2het[13] . There is no change in het ram instructions[25]. Het ram flag is always constant. I  have no idea how I can continue .If you have any idea, please share with me.

  • 0 in reply to user6300884
    TI__Guru**** 196306 points

    Does the emulated SCI work with the default pins (0 and 2)? Do you make any modification in HALCoGen configuration GUI and generate new code? If yes, the code in NHET RAM is replaced with PWM/CAP code generated by HALCoGen.