AnsweredAssumed Answered

Cannot connect to the target through SWD.

Question asked by guo.kelvin on May 14, 2015
Latest reply on May 22, 2015 by guo.kelvin
I could not connect the target (STM32F103ZET6) through ST-LINK or j-link(Both emulators are work well on other demo boards).
The MCU is powered by at 2.7V. Strangely , I've checked all the connections of the SWD interface and they seems ok. A 10kR pull-down was connected to SWCLK and a 10kR pull-up was connected to SWDIO
I put the probes on the SWDIO and SWCLK signal(CH1:SDIO,CH2:SWCLK,CH3:VDD) and the SWDIO waveform look very strange. It seems it can not be pull down to zero in some period but not all the time.Removing the pull-up resistor on SWDIO also doesn't help!

Is anyone see this before? The MCU is a brand new one and I believe should be no program on it.
9667f369946e76aeb8d74286e2dddc38_630.png
42fe6263e361ce8b47aa79d88272a988_357.png
4a24bfbe3d7d077d3f4f00b945359f2a_434.png

Outcomes