micro2440 16进制轉換

請各位幫忙一下 2440 這塊板子 放了我自己寫的程序
從網路UDP協定中抓取封包資料，再將資料轉成16进制傳送給串口(RS232)
但是程序處理過程遇到了sscanf這個函式無法轉換格式，例如1 1 1 09 0A 1B  轉出來都是 0 0 0 0 0 0

     pi = strtok(ptrmsg, " ");
            count =1;
            for (po = out; pi; pi = strtok(0, " ")) {
            if(count<=4)
            {
                            sscanf(pi, "%d", &u);
                        }
            else{
                             sscanf(pi, "%X", &u);
                        }
            kof++;
            po += sprintf(po, "%02X ", u);
            }
            *--po = 0;