JTAG下载程序出错，串口也不能下载了

土豆烧豆角

使用J-Link下载程序后，提示No Cortex-M Device found in JTAG Chain,PLease check the J-TAG cable and the connected devices.之前下载程序有时候好用有时候不好用，现在都不好用了，换成串口下载也下载不了了。难道是芯片坏了吗?求帮忙，谢谢大家！

JLink info:
------------
DLL: V4.15n, compiled Jun 18 2010 19:55:09
Firmware: J-Link ARM V8 compiled Nov 14 2012 22:34:52
Hardware: V8.00
S/N : 99999994 
Feature(s) : RDI,FlashDL,FlashBP,JFlash,GDBFULL 
 
* JLink Info: Could not measure total IR len. TDO is constant high.
**JLink Warning: No matching core found.
* 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 Error: Could not find supported CPU core on JTAG chain
Bad JTAG communication: Write to IR: Expected 0x1, got 0x7 (TAP Command : 2) @ Off 0x5.
Load "..\\output\\nfr2410.AXF" 
Set JLink Project File to "C:\Documents and Settings\Administrator\桌面\SPI发送0xcd\数据发送正常spi\users\JLinkSettings.ini"
 
JLink info:
------------
DLL: V4.15n, compiled Jun 18 2010 19:55:09
Firmware: J-Link ARM V8 compiled Nov 14 2012 22:34:52
Hardware: V8.00
S/N : 99999994 
Feature(s) : RDI,FlashDL,FlashBP,JFlash,GDBFULL 
 
* JLink Info: Could not measure total IR len. TDO is constant high.
**JLink Warning: No matching core found.
* 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 Error: Could not find supported CPU core on JTAG chain
Bad JTAG communication: Write to IR: Expected 0x1, got 0x7 (TAP Command : 2) @ Off 0x5.

伤剑使者

 这个问题倒是没见到过，不过jtag和串口下载没什么关系吧，你看一下是不是配置的问题，在者可以看一下jtag和芯片连接的问题

土豆烧豆角

zhe
这个是我的错误 是CPU坏了吗？JTAG 我都没动过，以前有时候可以下载有时候不能下载，现在一次都不行了。今天我用了一下串口下载，没反应啊，都是超时。