I have done the fpga flow in orpsocv2 on xilinx atlys board. All constraints was met. Then I want to test newlib on atlys.I have writen a simple ansi c promgram #include "stdio.h" #include "math.h" int main() { int sum,x,y,z; printf("Please input x,y,z!\n"); scanf("%d,%d,%d",&x,&y,&z); sum = x+y+z; printf("x is: %d\n",x); printf("y is: %d\n",y); printf("z is: %d\n",z); printf("sum is: %d\n",sum); } I compiled it with or32-elf-gcc and upload to the atlys ram with or_debug_proxy (gdb) target remote localhost:55555 Remote debugging using localhost:55555 _vfprintf_r (data=Cannot access memory at address 0x2c ) at ../../../../../unisrc/newlib/libc/stdio/vfprintf.c:1382 1382 ../../../../../unisrc/newlib/libc/stdio/vfprintf.c: No such file or directory. in ../../../../../unisrc/newlib/libc/stdio/vfprintf.c (gdb) load Loading section .vectors, size 0x2000 lma 0x0 Loading section .init, size 0x28 lma 0x2000 Loading section .text, size 0x16838 lma 0x2028 Loading section .fini, size 0x1c lma 0x18860 Loading section .rodata, size 0x1200 lma 0x1887c Loading section .eh_frame, size 0x4 lma 0x19a7c Loading section .ctors, size 0x8 lma 0x1ba80 Loading section .dtors, size 0x8 lma 0x1ba88 Loading section .jcr, size 0x4 lma 0x1ba90 Loading section .data, size 0xa30 lma 0x1ba94 Start address 0x2028, load size 107716 Transfer rate: 144 KB/sec, 3077 bytes/write. (gdb) c Continuing. ^C [Thread ] #1 stopped. __uart_getc () at ../../../../unisrc/libgloss/or32/uart.c:129 Line number 129 out of range; ../../../../unisrc/libgloss/or32/uart.c has 13 lines. at last The uart terminal only display "Please input x,y,z!" and cannot input anything but it test well in or1ksim. what's the matter? Is this a hardware problem or software problem? thanks