Holding TCK high while wiggling TMS/TDI?

Started by gs001, October 13, 2018, 03:20:46 am

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gs001

Hi,

Using ARM-USB-TINY-H with the ARM-JTAG-SWD adapter, is it possible to write an OpenOCD script that holds TCK high while wiggling TMS and TDI?   (That is, without pulsing TCK).  I don't need for this pattern to be fast, I just hope it is possible regardless of speed.  If there's a way to brute-force something using ftdi_layout_signal and ftdi_set_signal calls, that'd be fine for what I'm trying to do (drive a cJTAG escape sequence).

Any insights appreciated, thanks!

JohnS


gs001

I'll ask there too, but from the OpenOCD side I'm pretty sure they'll say "use ftdi_layout_signal and ftdi_set_signal", but for those I have to know what arguments to use to those commands to identify TCK/TMS/TDI in the particular pinout, in this case it's the Olimex ARM USB Tiny H and the SWD adapter.  So I'm slightly more hopeful of getting insights here than on the OpenOCD mailing list (but thanks I will try asking there too, and hopefully between the two maybe someone knows).