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STM32 newbie question

Question asked by xu.xiaoqiang on Aug 24, 2012
Latest reply on Aug 25, 2012 by xu.xiaoqiang
Hi ,
I'm new to STM32. Just designed a new board and assembled a prototype, but it does not work. when I connect J-link to it through SWD (three wires) interface, and start debugging, uVision4 gives these warnings:
========================================================
**JLink Warning: RESET (pin 15) high, but should be low. Please check target hardware.
***JLink Error: Supply voltage too low (1 Volt is required, Measured: 0.0 Volt).
Please check target power.
=====================================================
then a dialog pop up with the message "No Cortex-M SW Device Found".
My device is STM32F100C8T6. I measured voltages at the three VDD pins (pins 24,36, 48), they are 3.3V, as expected, VBAT(pin 1) and VDDA(pin 9) are connected to VDD as well.
The way I connected SWD to Jlink is: Gnd to pin1 on Jlink 20-pin connector, pin 37(SWCLK) connects to pin 9 on Jlink 20-pin connector, and pin 34(SWDIO) connects to pin 7 on Jlink 20-pin connector. This configuration works for the STM32 dev board I bought, but not on my own board.
Can any one suggest what could be possible cause of the problem?

Thanks
xiaoqiang

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