diff --git a/EC20xlib.cpp b/EC20xlib.cpp
new file mode 100644
index 0000000..92ab58a
--- /dev/null
+++ b/EC20xlib.cpp
@@ -0,0 +1,475 @@
+#include <Arduino.h>
+#include "EC20xlib.h"
+
+#define min _min
+#define max _max
+
+
+/////////////////////////////////////////////
+// Public methods.
+//
+
+EC20xlib::EC20xlib(Stream &serial) {
+#ifndef ESP32
+#ifdef ESP8266
+    EC20xconn = new SoftwareSerial(receivePin, transmitPin, false, 1024);
+#else
+    EC20xconn = new SoftwareSerial(receivePin, transmitPin, false);
+
+#endif
+    EC20xconn->setTimeout(100);
+#else
+    EC20xconn = &serial;
+    
+    EC20xconn->setTimeout(100);//阻塞时间
+#endif
+}
+
+
+EC20xlib::~EC20xlib() {
+
+    //delete EC20xconn;
+}
+
+
+// Block until the module is ready.
+byte EC20xlib::blockUntilReady(long baudRate) {
+
+    byte response = EC20x_NOTOK;
+    while (EC20x_OK != response) {
+        response = begin();
+        // This means the modem has failed to initialize and we need to reboot
+        // it.
+        if (EC20x_FAILURE == response) {
+            return EC20x_FAILURE;
+        }
+        delay(1000);
+        logln("Waiting for module to be ready...");
+    }
+    return EC20x_OK;
+}
+
+
+// Initialize the software serial connection and change the baud rate from the
+// default (autodetected) to the desired speed.
+byte EC20xlib::begin() {
+
+    EC20xconn->flush();
+
+    // Factory reset.
+    if (EC20x_OK != EC20xcommand("AT", "OK", "yy", EC20x_CMD_TIMEOUT, 20, NULL)) return EC20x_FAILURE;
+
+    // Echo off.
+    if (EC20x_OK != EC20xcommand("ATE0", "OK", "yy", EC20x_CMD_TIMEOUT, 2, NULL)) return EC20x_FAILURE;
+
+    // Echo off.
+    if (EC20x_OK != EC20xcommand("ATI", "OK", "yy", EC20x_CMD_TIMEOUT, 2, NULL)) return EC20x_FAILURE;
+    // 检查SIM卡是否在位
+    if (EC20x_OK != EC20xcommand("AT+CPIN?", "+CPIN: READY", "yy", EC20x_CMD_TIMEOUT, 2, NULL)) return EC20x_FAILURE;
+
+    // 检查CSQ
+    if (EC20x_OK != EC20xcommand("AT+CSQ", "OK", "yy", EC20x_CMD_TIMEOUT, 2, NULL)) return EC20x_FAILURE;
+
+    // 查看是否注册GSM网络
+    if (EC20x_OK != EC20xcommand("AT+CREG?", "+CREG: 0,1", "+CREG: 0,5", EC20x_CMD_TIMEOUT, 20, NULL)) return EC20x_FAILURE;
+
+    // 查看是否注册GPRS网络
+    if (EC20x_OK != EC20xcommand("AT+CGREG?", "+CGREG: 0,1", "+CGREG: 0,5", EC20x_CMD_TIMEOUT, 20, NULL)) return EC20x_FAILURE;
+
+    return EC20x_OK;
+}
+
+
+// Reboot the module by setting the specified pin HIGH, then LOW. The pin should
+// be connected to a P-MOSFET, not the EC20x's POWER pin.
+void EC20xlib::powerCycle(int pin) {
+    logln("Power-cycling module...");
+
+    powerOff(pin);
+
+    delay(2000);
+
+    powerOn(pin);
+
+    // Give the module some time to settle.
+    logln("Done, waiting for the module to initialize...");
+    delay(20000);
+    logln("Done.");
+
+    EC20xconn->flush();
+}
+
+
+// Turn the modem power completely off.
+void EC20xlib::powerOff(int pin) {
+    pinMode(pin, OUTPUT);
+    digitalWrite(pin, LOW);
+}
+
+
+// Turn the modem power on.
+void EC20xlib::powerOn(int pin) {
+    pinMode(pin, OUTPUT);
+    digitalWrite(pin, HIGH);
+}
+
+// Get the strength of the GSM signal.
+int EC20xlib::getSignalStrength() {
+    String response = "";
+    uint32_t respStart = 0;
+    int strength, error  = 0;
+
+    // Issue the command and wait for the response.
+    EC20xcommand("AT+CSQ", "OK", "+CSQ", EC20x_CMD_TIMEOUT, 2, &response);
+
+    respStart = response.indexOf("+CSQ");
+    if (respStart < 0) {
+        return 0;
+    }
+
+    sscanf(response.substring(respStart).c_str(), "+CSQ: %d,%d",
+           &strength, &error);
+
+    // Bring value range 0..31 to 0..100%, don't mind rounding..
+    strength = (strength * 100) / 31;
+    return strength;
+}
+
+/************************************************
+*函数名：ReadCCID
+*功能  ：读取SIM卡CCID号
+*参数  ：DataBuf（输出）  CCID号码缓存  应大于20
+*返回  : 0 成功 1 失败
+************************************************/
+byte EC20xlib::Read_CCID(char *DataBuf)
+{
+    uint8_t re = 0;
+    uint32_t respStart = 0;
+    String response = "";
+    //发送读取IMSI命令
+    re=EC20xcommand("AT+CCID\r\n","+CCID","yy",EC20x_CMD_TIMEOUT, 2, &response);
+    Serial.println(response);
+    respStart = response.indexOf("+CCID");
+    if (respStart < 0) {
+        return 0;
+    }
+    sscanf(response.substring(respStart).c_str(), "+CCID: %s",DataBuf);
+
+    return re;
+}
+/************************************************
+*函数名：EC20_Read_IMEI
+*功能  ：读取模块IMEI号
+*参数  ：DataBuf（输出）  IMEI号码缓存  应大于20
+*返回  : 0 成功 1 失败
+************************************************/
+byte EC20xlib::Read_IMEI(char *DataBuf)
+{
+    uint8_t re = 0;
+    String response = "";
+    //发送读取IMSI命令
+    re = EC20xcommand("AT+GSN","OK","yy",EC20x_CMD_TIMEOUT, 2, &response);
+    Serial.println(response);
+    
+    response = response.substring(2, 18);
+    Serial.println(response);
+    response.toCharArray(DataBuf,16,0);
+    Serial.println(DataBuf);
+    return re;
+}
+
+// Get the real time from the modem. Time will be returned as yy/MM/dd,hh:mm:ss+XX
+String EC20xlib::getRealTimeClock() {
+    String response = "";
+
+    // Issue the command and wait for the response.
+    EC20xcommand("AT+CCLK?", "OK", "yy", EC20x_CMD_TIMEOUT, 1, &response);
+    int respStart = response.indexOf("+CCLK: \"") + 8;
+    response.setCharAt(respStart - 1, '-');
+
+    return response.substring(respStart, response.indexOf("\""));
+}
+
+/////////////////////////////////////////////
+// Private methods.
+//
+
+// Read some data from the EC20x in a non-blocking manner.
+String EC20xlib::read() {
+    String reply = "";
+    if (EC20xconn->available()) {
+        reply = EC20xconn->readString();
+    }
+
+    // XXX: Replace NULs with \xff so we can match on them.
+    for (int x = 0; x < reply.length(); x++) {
+        if (reply.charAt(x) == 0) {
+            reply.setCharAt(x, 255);
+        }
+    }
+    return reply;
+}
+
+// 发送AT命令
+// Issue a command.
+byte EC20xlib::EC20xcommand(const char *command, const char *resp1, const char *resp2, int timeout, int repetitions, String *response) {
+    byte returnValue = EC20x_NOTOK;
+    byte count = 0;
+
+    // Get rid of any buffered output.
+    EC20xconn->flush();
+
+    while (count < repetitions && returnValue != EC20x_OK) {
+        log("Issuing command: ");
+        logln(command);
+
+        EC20xconn->write(command);
+        EC20xconn->write('\r');
+
+        if (EC20xwaitFor(resp1, resp2, timeout, response) == EC20x_OK) {
+            returnValue = EC20x_OK;
+        } else {
+            returnValue = EC20x_NOTOK;
+        }
+        count++;
+    }
+    return returnValue;
+}
+
+
+// Wait for responses.
+byte EC20xlib::EC20xwaitFor(const char *resp1, const char *resp2, int timeout, String *response) {
+    unsigned long entry = millis();
+    String reply = "";
+    byte retVal = 99;
+    do {
+        reply += read();
+#ifdef ESP8266
+        yield();
+#endif
+    } while (((reply.indexOf(resp1) + reply.indexOf(resp2)) == -2) && ((millis() - entry) < timeout));
+
+    if (reply != "") {
+        log("Reply in ");
+        log((millis() - entry));
+        log(" ms: ");
+        logln(reply);
+    }
+
+    if (response != NULL) {
+        *response = reply;
+    }
+
+    if ((millis() - entry) >= timeout) {
+        retVal = EC20x_TIMEOUT;
+        logln("Timed out.");
+    } else {
+        if (reply.indexOf(resp1) + reply.indexOf(resp2) > -2) {
+            logln("Reply OK.");
+            retVal = EC20x_OK;
+        } else {
+            logln("Reply NOT OK.");
+            retVal = EC20x_NOTOK;
+        }
+    }
+    return retVal;
+}
+
+// Read some data from the EC20x in a non-blocking manner.
+byte EC20xlib::connectMqttServer(char *clientID,char *ip,char *port,char *username,char *password) {
+    char sendbuf[100];
+    String response = "";
+
+    uint32_t respStart = 0;
+    int client_idx = 0, error = 0,result = 0;
+    for(int i = 0; i<2;i++)
+    {
+        sprintf(sendbuf,"AT+QMTOPEN=0,\"%s\",%s",ip,port);
+        if (EC20x_OK == EC20xcommand(sendbuf, "+QMTOPEN:", "yy", EC20x_CMD_TIMEOUT+3000, 3, &response)) 
+        {
+            respStart = response.indexOf("+QMTOPEN:");
+            if (respStart < 0) {
+                return EC20x_FAILURE;
+            }
+            sscanf(response.substring(respStart).c_str(), "+QMTOPEN: %d,%d",
+            &client_idx, &error);
+            
+            if(error == EC20x_OK)//连接成功
+            {
+                sprintf(sendbuf,"AT+QMTCONN=0,\"%s\",\"%s\",\"%s\"",clientID,username,password);
+                if (EC20x_OK == EC20xcommand(sendbuf, "+QMTCONN:", "yy", EC20x_CMD_TIMEOUT+3000, 3,  &response))
+                {
+                    respStart = response.indexOf("+QMTCONN:");
+                    if (respStart < 0) {
+                        return EC20x_FAILURE;
+                    }
+                    sscanf(response.substring(respStart).c_str(), "+QMTCONN: %d,%d,%d",
+                    &client_idx,&result, &error);
+                    if(error == EC20x_OK)
+                    {
+                        return EC20x_OK;
+                        logln("connect OK.");
+                    }
+                    else return EC20x_FAILURE;
+                }
+                else return EC20x_FAILURE;
+            }
+            else if(error == 2)//MQTT 标识符被占用,需要先断开重新连接
+            {
+                if (EC20x_OK != EC20xcommand("AT+QMTCLOSE=0", "+QMTCLOSE: 0,0", "yy", EC20x_CMD_TIMEOUT+3000, 3,  &response))
+                    return EC20x_FAILURE;
+            }
+            else return EC20x_FAILURE;
+        }
+        else return EC20x_FAILURE;
+    }
+    return EC20x_FAILURE;       
+    /*
+    sprintf(sendbuf,"AT+QMTOPEN=0,\"%s\",%s",ip,port);
+    if (EC20x_OK != EC20xcommand(sendbuf, "+QMTOPEN: 0,0", "yy", EC20x_CMD_TIMEOUT+3000, 3, &response)) 
+    {
+        if (EC20x_OK != EC20xcommand("AT+QMTCLOSE=0", "+QMTCLOSE: 0,0", "yy", EC20x_CMD_TIMEOUT+3000, 3,  &response))
+            return EC20x_FAILURE;
+        if (EC20x_OK != EC20xcommand(sendbuf, "+QMTOPEN: 0,0", "yy", EC20x_CMD_TIMEOUT+3000, 3,  &response))
+            return EC20x_FAILURE;
+    }
+    
+    memset(sendbuf,0,sizeof(sendbuf));
+    sprintf(sendbuf,"AT+QMTCONN=0,\"%s\",\"%s\",\"%s\"",clientID,username,password);
+    if (EC20x_OK != EC20xcommand(sendbuf, "+QMTCONN: 0,0,0", "yy", EC20x_CMD_TIMEOUT, 3,  &response)) return EC20x_FAILURE;
+    logln("connect OK.");
+    
+    return EC20x_OK;
+    */
+}
+
+/*
+取消订阅主题
+*/
+byte EC20xlib::UnSubTopic(char *topic,uint8_t qos1)
+{
+  char data_buff[300];//格式化AT指令时使用
+    
+  logln("UnSubTopic");
+  //订阅需要的主题
+  sprintf(data_buff,"AT+QMTUNS=0,%d,%s",1,topic);
+  if (EC20x_OK != EC20xcommand(data_buff,"OK","yy",5000,5,NULL)) return EC20x_FAILURE;
+	return EC20x_OK;
+}
+/*
+订阅主题
+*/
+byte EC20xlib::SubTopic(char *topic,uint8_t qos1)
+{
+  char data_buff[300];//格式化AT指令时使用
+    
+  logln("SubTopic");
+  //订阅需要的主题
+  sprintf(data_buff,"AT+QMTSUB=0,%d,\"%s\",%d",1,topic,qos1);
+  if (EC20x_OK != EC20xcommand(data_buff,"OK","yy",5000,5,NULL)) return EC20x_FAILURE;
+	return EC20x_OK;
+}
+/*
+发布主题
+*/
+byte EC20xlib::PubTopic(char *topic,char* msg,uint8_t qos1)//typ_NEC_AQData  *AQData_Send,
+{
+  char data_buff[300];//格式化AT指令时使用
+    
+  logln("PubTopic");
+  sprintf(data_buff,"AT+QMTPUBEX=0,0,%d,0,\"%s\",%d",qos1,topic,strlen(msg));
+  if (EC20x_OK != EC20xcommand(data_buff,">","yy",5000,5,NULL)) return EC20x_FAILURE;
+  if (EC20x_OK != EC20xcommand(msg,"OK","yy",5000,5,NULL)) return EC20x_FAILURE;
+  return EC20x_OK;
+}
+
+/*
+发布主题
+*/
+byte EC20xlib::getMessage(char *topic,char* msg,uint8_t qos1)//typ_NEC_AQData  *AQData_Send,
+{  
+    unsigned long entry = millis();
+    int commaPosition,last_commaPosition;//存储还没有分离出来的字符串
+    String reply = "";
+    byte retVal = 99;
+        reply += read();
+#ifdef ESP32
+        yield();
+#endif
+    if (reply != "") {
+        log("Reply in ");
+        log((millis() - entry));
+        log(" ms: ");
+        logln(reply);
+        if(reply.indexOf("+QMTRECV:") != -1)
+        {
+            logln("recv data");
+            uint8_t i = 0;
+            for(i = 0;i<3;i++)
+            {
+                commaPosition = reply.indexOf(',');//检测字符串中的逗号
+            
+                if(commaPosition != -1)//如果有逗号存在就向下执行
+                {
+                    if(i == 2)//获取topic
+                    {
+                       logln( reply.substring(1,commaPosition-1));//打印出第一个逗号位置的字符串
+                        reply.substring(1,commaPosition-1).toCharArray(topic,reply.substring(1,commaPosition-1).length()+1);
+                    }
+                    
+                    reply = reply.substring(commaPosition+1, reply.length());//打印字符串，从当前位置+1开始
+                }
+            }
+            if(1)//获取topic的内容
+            {
+                commaPosition = reply.indexOf('"');
+                last_commaPosition = reply.lastIndexOf('"');
+                logln( reply.substring(commaPosition+1,last_commaPosition));//打印出第一个逗号位置的字符串
+                reply.substring(commaPosition+1,last_commaPosition).toCharArray(msg,reply.substring(commaPosition+1,last_commaPosition).length()+1);
+            }  
+            retVal = EC20x_OK;
+        }
+        if(reply.indexOf("+QMTSTAT:") != -1)
+        {
+            logln("mqtt disconnect");
+            /*
+            <client_idx>  整型。MQTT 客户端标识符。
+            <err_code>  整型。错误代码。详细信息请参考下表。 
+
+            1  连接被服务器断开或者重置       执行 AT+QMTOPEN 重建 MQTT 连接 
+            2  发送 PINGREQ 包超时或者失败   首先反激活 PDP，然后再激活 PDP 并重建MQTT 连接。 
+            3  发送 CONNECT 包超时或者失败   1.  查看输入的用户名和密码是否正确。 
+                                            2.  确保客户端 ID 未被占用。 
+                                            3.  重建 MQTT 连接，并尝试再次发送CONNECT 包到服务器。 
+            4  接收 CONNACK 包超时或者失败   1.  查看输入的用户名和密码是否正确。 
+                                            2.  确保客户端 ID 未被占用。 
+                                            3.  重建 MQTT 连接，并尝试再次发送CONNECT 包到服务器。 
+            5  客户端向服务器发送 DISCONNECT 包，但
+               是服务器主动断开 MQTT 连接     正常流程。 
+            6  因为发送数据包总是失败，客户端主动断开MQTT 连接      1.  确保数据正确。 
+                                                                2.  可能因为网络拥堵或者其他错误，尝试重建 MQTT 连接。 
+            7  链路不工作或者服务器不可用  确保当前链路或者服务器可用。 
+            8  客户端主动断开 MQTT 连接  尝试重建连接。 
+            9~255  留作将来使用   
+            */
+            //重新连接
+            retVal = EC20x_DISCONNECT;
+        }
+        if(reply.indexOf("+QMTPUBEX:") != -1)
+        {
+            logln("rev the result of public message");
+            /*
+            <client_idx>  整型。MQTT 客户端标识符。范围：0~5。
+            <msgid>  整型。数据包消息标识符。范围：0~65535。只有当<qos>=0 时，该参数值为 0。
+            <result>  整型。命令执行结果。 
+            0  数据包发送成功且接收到服务器的 ACK（当<qos>=0 时发布了数据，则无需 ACK） 
+            1  数据包重传 
+            2  数据包发送失败
+            */
+            //接收到发送返回
+            retVal = EC20x_DISCONNECT;
+        }
+        
+    }
+    return retVal;
+}
diff --git a/EC20xlib.h b/EC20xlib.h
new file mode 100644
index 0000000..c7b85a5
--- /dev/null
+++ b/EC20xlib.h
@@ -0,0 +1,57 @@
+#ifndef EC20xlib_h
+#define EC20xlib_h
+
+#include <Arduino.h>
+
+#define DEBUG
+#ifdef DEBUG
+#define log(msg) Serial.print(msg)
+#define logln(msg) Serial.println(msg)
+#else
+#define log(msg)
+#define logln(msg)
+#endif
+
+#define countof(a) (sizeof(a) / sizeof(a[0]))
+
+#define EC20x_OK          0
+#define EC20x_NOTOK       1
+#define EC20x_TIMEOUT     2
+#define EC20x_FAILURE     3
+#define EC20x_DISCONNECT  4
+
+#define EC20x_CMD_TIMEOUT 2000
+
+//#define EC20xconn Serial2
+
+class EC20xlib {
+public:
+    EC20xlib(Stream &serial);
+    ~EC20xlib();
+
+    byte begin();
+    byte blockUntilReady(long baudRate);
+
+    void powerCycle(int pin);
+    void powerOn(int pin);
+    void powerOff(int pin);
+
+    int getSignalStrength();
+    String getRealTimeClock();
+    
+    byte connectMqttServer(char *clientID,char *ip,char *port,char *username,char *password);
+    byte SubTopic(char *topic,uint8_t qos1);
+    byte PubTopic(char *topic,char* msg,uint8_t qos1);
+    byte UnSubTopic(char *topic,uint8_t qos1);
+    byte getMessage(char *topic,char* msg,uint8_t qos1);
+    byte Read_CCID(char *DataBuf);
+    byte Read_IMEI(char *DataBuf);
+private:
+    Stream* EC20xconn;
+    String read();
+    byte EC20xcommand(const char *command, const char *resp1, const char *resp2, int timeout, int repetitions, String *response);
+    byte EC20xwaitFor(const char *resp1, const char *resp2, int timeout, String *response);
+    long detectRate();
+    char setRate(long baudRate);
+};
+#endif
diff --git a/LICENSE.md b/LICENSE.md
new file mode 100644
index 0000000..87c0133
--- /dev/null
+++ b/LICENSE.md
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2016 Stavros Korokithakis
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/README.md b/README.md
index b52ede1..f6b4de6 100644
--- a/README.md
+++ b/README.md
@@ -1 +1,2 @@
-# EC20x_lib
\ No newline at end of file
+# EC20x_lib
+
diff --git a/keywords.txt b/keywords.txt
new file mode 100644
index 0000000..7edf2ff
--- /dev/null
+++ b/keywords.txt
@@ -0,0 +1,35 @@
+#######################################
+# A6 GSM communication module
+# (esp8266)
+#######################################
+
+#######################################
+# Datatypes (KEYWORD1)
+#######################################
+
+EC20xlib	KEYWORD1
+callInfo	KEYWORD1
+
+#######################################
+# Methods and Functions (KEYWORD2)
+#######################################
+
+begin	KEYWORD2
+powerCycle	KEYWORD2
+
+dial	KEYWORD2
+redial	KEYWORD2
+hangUp	KEYWORD2
+checkCallStatus	KEYWORD2
+getSignalStrength	KEYWORD2
+
+sendSMS	KEYWORD2
+
+setVol	KEYWORD2
+enableSpeaker	KEYWORD2
+
+EC20xconn	KEYWORD2
+
+#######################################
+# Constants (LITERAL1)
+#######################################
diff --git a/library.json b/library.json
new file mode 100644
index 0000000..e203fca
--- /dev/null
+++ b/library.json
@@ -0,0 +1,14 @@
+{
+    "name": "EC20xlib",
+    "keywords": [
+      "EC20", "GSM", "CAT1", "mobile"
+    ],
+    "description": "An ESP8266/Arduino library for communicating with the EC20 cat1 module.",
+    "repository":
+    {
+        "type": "git",
+        "url": "https://github.com/luyang14/EC20x_lib.git"
+    },
+    "frameworks": "arduino",
+    "platforms": "*"
+}
diff --git a/library.properties b/library.properties
new file mode 100644
index 0000000..c3e3ef0
--- /dev/null
+++ b/library.properties
@@ -0,0 +1,9 @@
+name=EC20xlib
+version=0.1.0
+author=Stavros Korokithakis
+maintainer=iotts 
+sentence=An ESP8266/ESP32/Arduino library for communicating with the EC20 CAT1 module.
+paragraph=
+category=Communication
+url=https://github.com/luyang14/EC20x_lib.git
+architectures=*
diff --git a/sscanf.cpp b/sscanf.cpp
new file mode 100644
index 0000000..bafaeea
--- /dev/null
+++ b/sscanf.cpp
@@ -0,0 +1,262 @@
+/*
+ * Copyright (c) 2000-2002 Opsycon AB  (www.opsycon.se)
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *  This product includes software developed by Opsycon AB.
+ * 4. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
+ * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <stdarg.h>
+#include <string.h>
+#include <ctype.h>
+
+#define MAXLN 200
+#define ISSPACE " \t\n\r\f\v\""
+
+size_t strcspn(const char *p, const char *s) {
+    int i, j;
+
+    for (i = 0; p[i]; i++) {
+        for (j = 0; s[j]; j++) {
+            if (s[j] == p[i]) {
+                break;
+            }
+        }
+        if (s[j]) {
+            break;
+        }
+    }
+    return (i);
+}
+
+char * _getbase(char *p, int *basep) {
+    if (p[0] == '0') {
+        switch (p[1]) {
+        case 'x':
+            *basep = 16;
+            break;
+        case 't':
+        case 'n':
+            *basep = 10;
+            break;
+        case 'o':
+            *basep = 8;
+            break;
+        default:
+            *basep = 10;
+            return (p);
+        }
+        return (p + 2);
+    }
+    *basep = 10;
+    return (p);
+}
+
+/*
+ *  _atob(vp,p,base)
+ */
+int _atob(uint32_t *vp, char *p, int base) {
+    uint32_t value, v1, v2;
+    char *q, tmp[20];
+    int digit;
+
+    if (p[0] == '0' && (p[1] == 'x' || p[1] == 'X')) {
+        base = 16;
+        p += 2;
+    }
+
+    if (base == 16 && (q = strchr(p, '.')) != 0) {
+        if (q - p > sizeof(tmp) - 1) {
+            return (0);
+        }
+
+        strncpy(tmp, p, q - p);
+        tmp[q - p] = '\0';
+        if (!_atob(&v1, tmp, 16)) {
+            return (0);
+        }
+
+        q++;
+        if (strchr(q, '.')) {
+            return (0);
+        }
+
+        if (!_atob(&v2, q, 16)) {
+            return (0);
+        }
+        *vp = (v1 << 16) + v2;
+        return (1);
+    }
+
+    value = *vp = 0;
+    for (; *p; p++) {
+        if (*p >= '0' && *p <= '9') {
+            digit = *p - '0';
+        } else if (*p >= 'a' && *p <= 'f') {
+            digit = *p - 'a' + 10;
+        } else if (*p >= 'A' && *p <= 'F') {
+            digit = *p - 'A' + 10;
+        } else {
+            return (0);
+        }
+
+        if (digit >= base) {
+            return (0);
+        }
+        value *= base;
+        value += digit;
+    }
+    *vp = value;
+    return (1);
+}
+
+/*
+ *  atob(vp,p,base)
+ *      converts p to binary result in vp, rtn 1 on success
+ */
+int atob(uint32_t *vp, char *p, int base) {
+    uint32_t v;
+    if (base == 0) {
+        p = _getbase(p, &base);
+    }
+    if (_atob(&v, p, base)) {
+        *vp = v;
+        return (1);
+    }
+    return (0);
+}
+
+/*
+ *  vsscanf(buf,fmt,ap)
+ */
+
+int vsscanf(const char *buf, const char *s, va_list ap) {
+    uint32_t             count, noassign, width, base, lflag;
+    const char     *tc;
+    char           *t, tmp[MAXLN];
+
+    count = noassign = width = lflag = 0;
+    while (*s && *buf) {
+        while (isspace(*s)) {
+            s++;
+        }
+        if (*s == '%') {
+            s++;
+            for (; *s; s++) {
+                if (strchr("dibouxcsefg%", *s)) {
+                    break;
+                }
+                if (*s == '*') {
+                    noassign = 1;
+                } else if (*s == 'l' || *s == 'L') {
+                    lflag = 1;
+                } else if (*s >= '1' && *s <= '9') {
+                    for (tc = s; isdigit(*s); s++);
+                    strncpy(tmp, tc, s - tc);
+                    tmp[s - tc] = '\0';
+                    atob(&width, tmp, 10);
+                    s--;
+                }
+            }
+            if (*s == 's') {
+                while (isspace(*buf)) {
+                    buf++;
+                }
+                if (!width) {
+                    width = strcspn(buf, ISSPACE);
+                }
+                if (!noassign) {
+                    strncpy(t = va_arg(ap, char *), buf, width);
+                    t[width] = '\0';
+                }
+                buf += width;
+            } else if (*s == 'c') {
+                if (!width) {
+                    width = 1;
+                }
+                if (!noassign) {
+                    strncpy(t = va_arg(ap, char *), buf, width);
+                    t[width] = '\0';
+                }
+                buf += width;
+            } else if (strchr("dobxu", *s)) {
+                while (isspace(*buf)) {
+                    buf++;
+                }
+                if (*s == 'd' || *s == 'u') {
+                    base = 10;
+                } else if (*s == 'x') {
+                    base = 16;
+                } else if (*s == 'o') {
+                    base = 8;
+                } else if (*s == 'b') {
+                    base = 2;
+                }
+                if (!width) {
+                    if (isspace(*(s + 1)) || *(s + 1) == 0) {
+                        width = strcspn(buf, ISSPACE);
+                    } else {
+                        width = strchr(buf, *(s + 1)) - buf;
+                    }
+                }
+                strncpy(tmp, buf, width);
+                tmp[width] = '\0';
+                buf += width;
+                if (!noassign) {
+                    atob(va_arg(ap, uint32_t *), tmp, base);
+                }
+            }
+            if (!noassign) {
+                count++;
+            }
+            width = noassign = lflag = 0;
+            s++;
+        } else {
+            while (isspace(*buf)) {
+                buf++;
+            }
+            if (*s != *buf) {
+                break;
+            } else {
+                s++, buf++;
+            }
+        }
+    }
+    return (count);
+}
+
+
+int __attribute__((used)) sscanf(const char *buf, const char *fmt, ...) {
+    int             count;
+    va_list ap;
+
+    va_start(ap, fmt);
+    count = vsscanf(buf, fmt, ap);
+    va_end(ap);
+    return (count);
+}