使用JTAG调试miniBfin板

1. 启动gdbproxy，要使用配置了libbfemu的版本
     # gdbproxy bfin
    
2. 启动gdb
     # bfin-uclinux-gdb
     (gdb)target remote : 2000
    
3. 使用gdb命令查看寄存器值
     1)PLL Divide register
     (gdb) p /x *0xffc00004
           => 0x0003 SSEL=3 CSEL=0
     2)PLL Control register
     (gdb) p /x *0xffc00000
           => 0x5000 DF=0 MSEL=40
     计算频率：
     if(!MSEL)
         VCO = CLKIN/(DF+1) * MSEL
     else
         VCO = CLKIN/(DF+1)
    
     CCLK = VCO/(2^CSEL) (core clock)
     SCLK = VCO/SSEL     (system clock)
     所以：
     输入晶阵10MHz,
     VCO = 10M/1 * 40 = 400MHz
     CCLK = 400M/(2^0) = 400MHz
     SCLK = 400M/3 = 133MHz
     3)SDRAM Memory Global Control Register
     (gdb) p /x *0xffc00a10
           => 0x801111cd
           CDDBG 0 - continue driving SDRAM
                     controls during bus grant
           TCSR  0 - 45 degrees C
           FBBRW 0 - Disabled
           EBUFE 0 - External buffering timing disabled
           SRFS  0 - Disable self-refresh
           PSSE  0 - No effect
           PSM   0 - Precharge, 8 CBR refresh cycles,
                     mode register set
           PUPSD 0 - No extra delay added before first
                     Precharge command
           TWR   10 - 2 cycles
           TRCD  010 - 2 cycles
           TRP   010 - 2 cycles
           TRAS  0111 - 7 cycles
           PASR  00 - All 4 banks refreshed
           CL    11 - 3 cycles
           SCTE  1 - Enabled
     4)SDRAM Memory Bank Control register
     (gdb) p /x *0xffc00a14
           => 0x13
           EBE   1 - Enabled
           EBSZ  01 - 32Mbyte
           EBCAW 01 - 9bits
     5)SDRAM Control Status Register
     (gdb) p /x *0xffc00a1c
           => 0x0001
           BGSTAT 0 - Bus not granted
           SDEASE - W1C 0 - No error detected
           SDRS   0 - SDRAM already powered up
           SDPUA  0 - SDC not in power up sequence
           SDSRA  0 - SDRAMs not in self-refresh mode
           SDCL   1 - SDC is idle
     6)SDRAM Refresh Rate Control Register
     (gdb) p /x *0xffc00a18
           => 0x0408

4. 查看Memory内容
   例如查看0x01ef0000开始的128字节的内容
   (gdb) x /128xh 0x01ef0000
  
   设置memory值
   (gdb) set *0x01ef0000 = 0x1168
   (gdb) p /x *0x01ef0000