今天不小心掉用了#define GPIO_Remap_SWJ_Disable ((uint32_t)0x00300400) /*!< Full SWJ Disabled (JTAG-DP + SW-DP) */
这个函数导致无法用Jlink下载程序
解决办法：
将stm32的REST脚一直接地，即复位，用keil下载，运行到
JLink info:
------------
DLL: V4.46f, compiled May 10 2012 08:30:05
Firmware: J-Link ARM V8 compiled Nov 28 2014 13:44:46
Hardware: V8.00
S/N : 1631096674
Feature(s) : RDI,FlashDL,FlashBP,JFlash,GDBFULL
* JLink Info: Found SWD-DP with ID 0x1BA01477
* JLink Info: Found SWD-DP with ID 0x1BA01477
* JLink Info: TPIU fitted.
* JLink Info: ETM fitted.
* JLink Info: FPUnit: 6 code (BP) slots and 2 literal slots
* JLink Info: Found Cortex-M3 r1p1, Little endian.
ROMTableAddr = 0xE00FF003
* JLink Info: Found SWD-DP with ID 0x1BA01477
* JLink Info: Found SWD-DP with ID 0x1BA01477
* JLink Info: TPIU fitted.
* JLink Info: ETM fitted.
* JLink Info: FPUnit: 6 code (BP) slots and 2 literal slots
* JLink Info: Found Cortex-M3 r1p1, Little endian.
松开复位键，继续下载，解决问题。
原文：http://www.cnblogs.com/duguqiuying/p/4533469.html