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TMS320F280049: About the use of Local Interconnect Network Module

Part Number: TMS320F280049


Hi all,

          Recently, Our product meet a problem about Local Interconnect Network Module of TMS320F280049. And the LIN chip we have used is NXP TJA1021. When the supply voltage of the LIN chip circuit happen the voltage sags( supply voltage:12V  sag to 6V (and last 2ms)),the communication will cut off immediately with the occurrence of undervoltage. The voltage sag to minimum 4.1v < the undervoltage protection point of LIN chip(NXP TJA1021) 4.7v.

           My issue is when this kind of case happen,why the LIN Module of DSP will stop working. And the voltage sags only last 2ms. when the supply voltage become correctly, why the LIN Module of DSP will not recover ?and which interrupt will happen in this case?

Best wishes, It is apprciated if you could give us a reply on this matter as soon as possible.

YJ

  • Hi,

    Looks like NXP TJA1021 goes in the SLEEP Mode when voltage sag happens, which keeps the TXD and RXD pins in the floating state. F280049 LIN will detect this as a Physical bus error or Bit Error (not completely sure, because it depends on what operation it was performing while the voltage sag happened).

    You can read the SCIFLR register to determine the error condition. Also do you connect SLP_N to the micro-controller? If you do then you may be able to wake up NXP TJA1021 on this event through F280049.

    Regards,

    Nirav

  • Hi Nirav,

    Thanks for your reply. SLP_N is always connect with High Level. And if this case happen,communication will not recover. And i will have more test to monitor the SCIFLR register.

    Thanks a lot.

    YJ