void hexdump(uint8_t *buf, uint32_t len)
{
int i = 0;
printf("----------------------hexdump------------------------");
for(i = 0; i < len; i++) {
printf("%02x ", buf[i]);
if( (i+1) % 16 == 0) {
printf("\n");
}
}
if(i%16 != 0) {
printf("\n");
}
printf("---------------------hexdump-------------------------\n");
}