Magnus Lundin wrote: > Michael Bruck wrote: > >> On Tue, May 26, 2009 at 7:47 PM, Magnus Lundin <lun...@mlu.mine.nu> wrote: >> >> >>> Spencer Oliver wrote: >>> >>> >>>>>> If you define your interface with only srst then the >>>>>> >>>>>> >>>>> software method >>>>> >>>>> >>>>>> will be used. >>>>>> Well it did last time i checked - see jtag_add_reset for code. >>>>>> >>>>>> >>>>>> >>>>>> >>>>> That code makes a move to TLR. This method is fine when you know in which >>>>> state you are, but not when OpenOCD is started and the previous TAP state >>>>> is >>>>> undefined. >>>>> >>>>> >>>>> >>>>> >>>> I have not dug into jtag.c for a while, i am pretty sure it was not the >>>> case. >>>> it was a few years back however that this support was originally added. >>>> >>>> Cheers >>>> Spen >>>> >>>> _______________________________________________ >>>> Openocd-development mailing list >>>> Openocd-development@lists.berlios.de >>>> https://lists.berlios.de/mailman/listinfo/openocd-development >>>> >>>> >>>> >>> move to TLR works for all current states. It is 7 steps with TMS high, that >>> takes you to TAP_RESET froma any starting state. >>> >>> >> Moving to TLR from an *unknown* state doesn't work because we pretend >> that there is no such thing as the TAP being in an unknown state. We >> rather initialize the boot state to be TAP_RESET. Which is not only >> false but also leads low level drivers to believe that nothing needs >> to be done. In particular the ft2232 driver says statemove TAP_RESET >> -> TAP_RESET is redundant and does not need to be executed (see >> ft2232_execute_statemove() ). >> >> >> >> > I have not had time look look closely into this but I think that what > must be decided is the exact semantics of state_move(end_state) > - Is it, as I think it should be : move to end_state, and if we are > already there do nothing ? > > Then the tlr call should be implemented , in jtag.c, with a path_move > of 7 tms=1 steps. This should work for all start states. And it easy to > implement and test witout major disruptions. > Definetly possible for 0.2.0 > > Looking into this I see that my suggestion will not work, path_move is even mork senitive to start states that state_move. But there must be some nice clean way to handle both situations. > Regards > Magnus > - > > _______________________________________________ > Openocd-development mailing list > Openocd-development@lists.berlios.de > https://lists.berlios.de/mailman/listinfo/openocd-development >
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