3 Replies Latest reply on Jan 9, 2017 3:02 PM by J.Pacheco

    Reassigning just theTRST_N pin (for debug output)


      Hey everyone,


      Is it physically possible to output from UART_B_TX while still debugging via JTAG?


      Specifically, I see that TRST_N is mux'd with UART_B_TX.  TRST_N is one of those JTAG pins which is technically optional (since a TAP reset can be asserted via either TRST_N or by holding TMS high for five clock cycles).


      The main documentation warns that disabling JTAG and assigning the pins to UART_B locks out JTAG--which is a good warning.  But I'm wondering if that doesn't apply if we only reassign pin TRST_N.


      I'm asking specifically "is this possible from a Quark D2000 perspective", and not in relation to the current build of OpenOCD.  I am working on custom JTAG debugger software for Quark micros--so there are no software limitations here.


      Thanks guys,