problem with jtag tck pin

Posted on June 01, 2013 at 08:55

hi

I have a problem

with jtag tck pin on my board.

When

I touch

it with

my

finger

  the st-link

Works properly

& connect to stm32f417 but if  i remove my finger from this pin the st-link not connect to my mcu.i pull-down tck pin with 10k to gnd.

Also, when

i connect my board's gnd to pc case

this

problem

can be

solved

.

What is

the problem?why tck pin is sensitive to the touch of my finger

???