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CCS/F28M35M52C: The chip can't connect to the emulator

Part Number: F28M35M52C

Tool/software: Code Composer Studio

My problem, I'm testing two identical circuit boards, using the chip is the F28M35, one of which works and the other can't connect the emulator. I tested the circuit board that didn't work, the chip input voltage(3.3v,1.8v,1.2v) was correct and the clock (25MHz)was correct.

However the the circuit board have some problem .the A_XRSTn and B_XRSTn levels of the reset pin are 1.5V, B_X1 the corresponding clock signal is biased by 200mv DC。

 

  • Can you elaborate on what other circuits(either active or passive or IC) is tied to both the XRSn and ARSn pins?  Are both pins tied together as recommended in the DS?

    Best,
    Matthew

  • The chip was re-welded and the reset problem disappeared, but when the emulator was connected, the following error occurred。

    /*********/
    This error is generated by TI's USCIF driver or utilities.

    The value is '-180' (0xffffff4c).
    The title is 'SC_ERR_CTL_NO_TRG_POWER'.

    The explanation is:
    The controller has detected a target power loss.
    The user must turn-on or connect the power supply for the target.

    /*********/

    My circuit schematic

    The forum's recommendations are as follows。

    I don't understand the  TVRef pin what the corresponding is?
    I tested a board that worked properly, with the same level of pins as the board that didn't work.

  • Pin 5 of the JTAG header is called the PD (Power Detect) pin in most of our documentation.  This error would mean that the debug probe didn't sense 3.3V on this pin.  Given that your schematic is showing this tied correctly the problem could be local to the PCB.  I would put a mulit-meter on that pin to make sure it has 3.3V when you board/MCU is powered.

    Best,

    Matthew