请问关于STM32的JTAG编程有关问题

请教关于STM32的JTAG编程问题
最近要做一个手持下载器，用AT89S52通过JTAG方式给STM32下载程序。由于原来没做过相关的东西，所以网上找了一下相关的资料，照着现有的历程测试了下，发现的以下几个问题

1，STM32对应的BSD文件中，写着  
attribute INSTRUCTION_OPCODE of STM32F103C8: entity is 
  "BYPASS (11111)," &
  "EXTEST (00000)," &
  "SAMPLE (00010)," &
  "PRELOAD (00010)," &
  "IDCODE (00001)";
那么我用IDCODE指令去读取CPUID，代码如下
  //P1_3 P1_5 P1_6引脚对应TDI TCK TMS
  //P3_0对应TDO

  #define JTAG_DELAY() _nop_() 
  #define JTAG_GET_TDO() ((P3_0==1) ? 1:0)

  void nvdJTAG_Set(unsigned char Control)
  {
P1 = Control;
  }

  void JTAG_ReadId(void)
  {
int i;
char id[32]；

JTAG_RunTestldleState();

nvdJTAG_Set(TDI_H | TMS_H | TCK_L);JTAG_DELAY();
nvdJTAG_Set(TDI_H | TMS_H | TCK_H);JTAG_DELAY(); // Select-DR Scan Status

nvdJTAG_Set(TDI_H | TMS_H | TCK_L);JTAG_DELAY();
nvdJTAG_Set(TDI_H | TMS_H | TCK_H);JTAG_DELAY(); // Select-IR Scan Status

nvdJTAG_Set(TDI_H | TMS_L | TCK_L);JTAG_DELAY();
nvdJTAG_Set(TDI_H | TMS_L | TCK_H);JTAG_DELAY(); // Capture-IR Status

nvdJTAG_Set(TDI_H | TMS_L | TCK_L);JTAG_DELAY();
nvdJTAG_Set(TDI_H | TMS_L | TCK_H);JTAG_DELAY(); // Shift-IR Status

//STM32F103XX IDCODE Instruction "00001"
nvdJTAG_Set(TDI_H | TMS_L | TCK_L);JTAG_DELAY();
nvdJTAG_Set(TDI_H | TMS_L | TCK_H);JTAG_DELAY(); // '1'

nvdJTAG_Set(TDI_L | TMS_L | TCK_L);JTAG_DELAY();
nvdJTAG_Set(TDI_L | TMS_L | TCK_H);JTAG_DELAY(); // '0'

nvdJTAG_Set(TDI_L | TMS_L | TCK_L);JTAG_DELAY();
nvdJTAG_Set(TDI_L | TMS_L | TCK_H);JTAG_DELAY(); // '0'

nvdJTAG_Set(TDI_L | TMS_L | TCK_L);JTAG_DELAY();
nvdJTAG_Set(TDI_L | TMS_L | TCK_H);JTAG_DELAY(); // '0'

nvdJTAG_Set(TDI_L | TMS_H | TCK_L);JTAG_DELAY();
nvdJTAG_Set(TDI_L | TMS_H | TCK_H);JTAG_DELAY(); // '0', //Exit1-IR

nvdJTAG_Set(TDI_H | TMS_H | TCK_L);JTAG_DELAY();
nvdJTAG_Set(TDI_H | TMS_H | TCK_H);JTAG_DELAY(); // Update_IR

nvdJTAG_Set(TDI_H | TMS_H | TCK_L);JTAG_DELAY();
nvdJTAG_Set(TDI_H | TMS_H | TCK_H);JTAG_DELAY(); // Select-DR-Scan

nvdJTAG_Set(TDI_H | TMS_L | TCK_L);JTAG_DELAY();
nvdJTAG_Set(TDI_H | TMS_L | TCK_H);JTAG_DELAY(); //Capture-DR

nvdJTAG_Set(TDI_H | TMS_L | TCK_L);JTAG_DELAY();
nvdJTAG_Set(TDI_H | TMS_L | TCK_H);JTAG_DELAY(); //Shift-DR

// Read IDcode..
for( i=0 ; i<=30 ; i++) {
nvdJTAG_Set(TDI_H | TMS_L | TCK_L);JTAG_DELAY();
nvdJTAG_Set(TDI_H | TMS_L | TCK_H);JTAG_DELAY(); //Shift-DR
id[i] = (char)JTAG_GET_TDO();
}

nvdJTAG_Set(TDI_H | TMS_H | TCK_L);JTAG_DELAY();
nvdJTAG_Set(TDI_H | TMS_H | TCK_H);JTAG_DELAY(); //Exit1_DR
id[i] = (char)JTAG_GET_TDO();

nvdJTAG_Set(TDI_H | TMS_H | TCK_L);JTAG_DELAY();
nvdJTAG_Set(TDI_H | TMS_H | TCK_H);JTAG_DELAY(); // Update_DR

nvdJTAG_Set(TDI_H | TMS_L | TCK_L);JTAG_DELAY(); //
nvdJTAG_Set(TDI_H | TMS_L | TCK_H);JTAG_DELAY(); // Run-Test/Idle
nvdJTAG_Set(TDI_H | TMS_L | TCK_L);JTAG_DELAY();
nvdJTAG_Set(TDI_H | TMS_L | TCK_H);JTAG_DELAY(); // Run-Test/Idle
nvdJTAG_Set(TDI_H | TMS_L | TCK_L);JTAG_DELAY();
nvdJTAG_Set(TDI_H | TMS_L | TCK_H);JTAG_DELAY(); // Run-Test/Idle
  }

可是取到的32位ID值，每一位总是常为1，不是正确值。现在STM32的板子可以通过ULink正常写程序。
请问这是怎么回事，是不是JTAG_DELAY()函数的延时不对？还是硬件上需要有特殊的电路？


------解决方案--------------------
您好
我现在也正在做stm32的手持下载器，一头雾水，能帮忙指点下吗，要访问stm32的flash寄存器，其jtag命令是什么？我的qq147171234 一起讨论下，我是用AVR单片机。
------解决方案--------------------
没具体弄过这方面的东西，MARK

帮顶下、