#define ITM_Port8(n) (*((volatile unsigned char *)(0xE0000000+4*n))) #define ITM_Port16(n) (*((volatile unsigned short*)(0xE0000000+4*n))) #define ITM_Port32(n) (*((volatile unsigned long *)(0xE0000000+4*n))) #define DEMCR (*((volatile unsigned long *)(0xE000EDFC))) #define TRCENA 0x01000000 l 在源代码中添加fputc函数,它向ITM的激励端口0寄存器写数据。如果有了fputc函数,则可以用printf函数做为调试输出。ITM的激励端口0与ITM Viewer窗口固定连接。
struct __FILE { int handle; /* Add whatever you need here */ }; FILE __stdout; FILE __stdin; int fputc(int ch, FILE *f) { if (DEMCR & TRCENA) { while (ITM_Port32(0) == 0); ITM_Port8(0) = ch; } return(ch); } l 在源代码中添加printf函数来显示调试跟踪信息。