stlink can not work normally: The Reset signal keep low when i push download button of iar.

100asong · ‎2011-12-27

Posted on December 27, 2011 at 14:29

hi,

stlink jtag can not work normally.The Reset signal keep low when i push download button of iar.

Tesla DeLorean · ‎2011-12-27

Posted on December 27, 2011 at 14:45

NRST is ZERO, processor NO function

How is the Reset on your board achieved? Nominally you want it driven open-collector/drain with a pull up. If your circuit drives the signal low, or you use push-pull drivers the chip will not reset properly.

Typically external JTAG pods cannot get the pin HIGH if other sources are driving it LOW.

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