JTAG口当I/O用后，下载不进程序了。。

tigerlikes

JTAG口当I/O用后，下载不进程序了。。 [复制链接]

JTAG 口当I/O 用后，用仿真器下载不进程序了。。
识别不了设置，No Cortex-M Device found in JTAG Chain
咋整的呀。？大家遇到过吗》？

valengu

从RAM BOOT即可。


我要求版主把这句话挂到版头上。。。。

xjtuwugang

呵呵，你把JTAG的引脚当作I/O引脚来用，原来的JTAG功能当然会失效了。

请按照2楼说的做。

yyyjjj

                                 呵呵

bassdiy

                                 你要下载程序，肯定不能配置成普通I/O口

stoutstone

Using serial wire and releasing the unused debug pins as GPIOs
To use the serial wire DP to release some GPIOs, the user software must set
SWJ_CFG=010 just after reset. This release PA15, PB3 and PB4 which now become
available as GPIOs.
When debugging, the host performs the following actions:
● Under system RESET, all SWJ pins are assigned (JTAG-DP + SW-DP)
● Under system RESET, the debugger host sends the JTAG sequence to switch from the
JTAG-DP to the SW-DP.
● Still under system RESET, the debugger sets a breakpoint on vector reset
● The System Reset is released and the Core halts.
● All the debug communications from this point are done using the SW-DP. The other
JTAG pins can then be reassigned as GPIOs by the user software.

5586

                                 按理说，下载程序的时候，应该处于复位状态或是  the Core halts  ，程序还没运行呀，此时I/O口还应该是默认的JTAG端口。。

ccdl

                                 从上电到调试器控制住内核，总归有段时间的，足够运行一些代码了。

forobr

                                 明白了，谢谢各位

good969

                                 一般JTAG口应该不用配置吧