我用kill4给stm32的板子烧程序的时候出现问题

显示No Crotex-M Device found in JTAG chain
上次烧的的时候还是好的啊。。。
在这次烧纸钱，我给板子接了近6.5V的电压，有点冒烟了，但是我看着没有哪里坏掉了
然后显示的是这个
* JLink Info: Could not measure total IR len. TDO is constant high.
**JLink Warning: No matching core found. Selecting default core (ARM7).
* JLink Info: Could not measure total IR len. TDO is constant high.
* JLink Info: Could not measure total IR len. TDO is constant high.
* JLink Info: Resetting target using RESET pin
* JLink Info: Halting CPU core
**JLink Warning: Received 0 as core Id.
* JLink Info: Using DBGRQ to halt CPU
* JLink Info: Resetting TRST in order to halt CPU
* JLink Info: Resetting target using RESET pin
* JLink Info: Halting CPU core
**JLink Warning: Received 0 as core Id.
* JLink Info: Using DBGRQ to halt CPU
* JLink Info: Resetting TRST in order to halt CPU
***JLink Error: Could not find supported CPU core on JTAG chain
Bad JTAG communication: Write to IR: Expected 0x1, got 0x0 (TAP Command : 2) @ Off 0x5.
Unable to halt ARM core
**JLink Warning: Target system has been power-cycled
* JLink Info: TotalIRLen = ?, IRPrint = 0x..000000000000000000000000
**JLink Warning: No matching core found. Selecting default core (ARM7).
* JLink Info: TotalIRLen = ?, IRPrint = 0x..000000000000000000000000
***JLink Error: Could not find supported CPU core on JTAG chain
到底是哪里出了问题啊，我在网上搜的说什么boot拉高位什么的。。。
我现在完全不懂arm啊。。。
哪位大神指导下啊。。。