采用UDP协议的PIC32MZ ethernet bootloader

经过千辛万苦，今天终于完工PIC32MZ EC Starter Kit的ethernet bootloader项目。我将整个项目, 命名为PhnBootloader。它分为两个部分。第一个部分是PC 端的host程序PhnLoader_v3.0。另一部分是单片机端boot程序PhnBoot_v3.0，是从Microchip AN1388 ethernet bootloader移植过来的。整个移植过程碰到很多困难，主要是由于ethernet bootloader使用到Microchip 的TCP/IP Stack，但是TCP/IP Stack不支持PIC32MZ。 这里我列出移植需要注意的地方：

1. PIC32MZ默认enable cache.

2. PIC32MZ ethernet module ports mapping

3. PIC32MZ EC Starter Kit的external PHY的LEDs和Start Kit的LED1,LED2复用

4. PIC32MZ EC Starter Kit的ethernet module有些port复用AN功能。

5. ethernet bootloader download完application后，跳转到application前 ，注意要清零所有使用到的register，包括disable interrupt。

　　PhnLoader_v3.0和PhnBoot_v3.0之间采用UDP协议通信，通信数据包格式采用以下协定：

...

STX - Start of packet indicator
ETX - End of packet indicator
LEN - The length of true data 
DATA - General data 16 bytes, only first LEN of datas are true
CMD - Base command
ADDR - Address up to 32 bits  ( ADDRL , ADDRH , ADDRH, ADDRM)

　　具体有以下Base command:

RD-VER:  0x00 -- Read Version Information （最终版本未实现）
RD_MEM： 0x01 -- Read Program Memory （最终版本未实现）
ER_MEM: 0x03 -- Erase Program Memory
WR_MEM： 0x02 -- Write Program Memory 
WR_CFG： 0x04 -- Write Configuration Registers （最终版本未实现）

　　PhnLoader_v3.0

　　PhnLoader_v3.0 是PC端host 程序。

      运行环境：Window + .NET Framework 4.5

      开发语言：C#

      通信类型：UDP Server

      IP 地址： 192.168.1.105

      端口号：  8720

      UI 如下图：

　　C#源代码主要部分：

            try
            {                while (loaderReader.Peek() >= 0)
                {
                    pBarLoading.PerformStep();
                    recordLine = loaderReader.ReadLine();                    if (recordLine.Contains(EXTEND_TOKEN) == true)
                    {                        if (recordLine.Contains(USER_ID_TOKEN) == true)
                        {
                            isNextLineUserID = true;                            continue;
                        }                        //else if (recordLine.Contains(CONFIG_BITS_TOKEN) == true)                        //{                        //    const int ADDR_U_START_INDEX = 9;                        //    const int ADDR_U_LENGTH = 4;                        //    string addrU = recordLine.Substring(ADDR_U_START_INDEX, ADDR_U_LENGTH);                        //    loaderUpperAddr = Convert.ToInt32(addrU, 16) << 16;                        //    isNextLineConfigBits = true;                        //    continue;                        //}
                        else if (recordLine.Contains(PIC32_CONFIG_BITS_TOKEN) == true)
                        {                            const int ADDR_U_START_INDEX = 9;                            const int ADDR_U_LENGTH = 4;                            string addrU = recordLine.Substring(ADDR_U_START_INDEX, ADDR_U_LENGTH);
                            loaderUpperAddr = Convert.ToInt32(addrU, 16) << 16;
                            isNextLineConfigBits = true;                            continue;
                        }                        else
                        {                            const int ADDR_U_START_INDEX = 9;                            const int ADDR_U_LENGTH = 4;                            string addrU = recordLine.Substring(ADDR_U_START_INDEX, ADDR_U_LENGTH);
                            loaderUpperAddr = Convert.ToInt32(addrU, 16) << 16;                            continue;
                        }
                    }                    else if (recordLine.Contains(END_OF_HEX_FILE_TOKEN) == true)
                    {                        break;
                    }                    if (isNextLineUserID)
                    {
                        isNextLineUserID = false;                        // do nothing;                    }                    else if (isNextLineConfigBits)
                    {                        //if (!DownloadConfigLine(recordLine))                        //{                        //    Debug.WriteLine("Error found during configuration bits programming");                        //    loaderReader.Close();                        //    loaderServer.Close();                        //    btnDownload.Enabled = true;                        //    return;                        //}                        DownloadConfigLine(recordLine);
                        isNextLineConfigBits = false;
                    }                    else
                    {                        if (!DownloadDataLine(recordLine))
                        {
                            Debug.WriteLine("Error found during data programming");
                            loaderReader.Close();
                            loaderServer.Close();
                            btnDownload.Enabled = true;                            return;
                        }
                    }
                }
            }            catch (Exception ex)
            {
                Debug.WriteLine("Error: " + ex.Message);
                textBoxStatus.ForeColor = Color.Red;
                textBoxStatus.AppendText("Downloading failed\r\n");
                textBoxStatus.ForeColor = Color.Black;
                loaderServer.Close();
                loaderReader.Close();
                btnDownload.Enabled = true;                return;
            }

　　PhnBoot_v3.0

　　PhnBoot_v3.0 是单片机端Boot 程序。

      运行环境：PIC32MZ EC Starter Kit

      开发语言：C 语言 （Microchip XC32编译）

      通信类型：UDP Client

      IP 地址： 192.168.1.123

      端口号：  8740

　　主要代码段：

        switch (GenUDPSt)
        {        case SM_HOME:
            ARPResolve(&ServerNode.IPAddr);
            startTime = TickGet();
            GenUDPSt++;            break;        case SM_ARP:            if (TickGet() - startTime < 5*TICK_SECOND)
            {                if (ARPIsResolved(&ServerNode.IPAddr,&ServerNode.MACAddr))
                {
                    MySock = UDPOpen(LOCAL_CLIENT_PORT,&ServerNode,REMOTE_SERVER_PORT);
                    startTime = TickGet();
                    GenUDPSt++; 
                }
            }            else
            {
                GenUDPSt = SM_HOME;
            }            break;        case SM_UDPOPEN:            if (TickGet() - startTime < TICK_SECOND)
            {                if (MySock != INVALID_UDP_SOCKET)
                {
                    startTime = TickGet();
                    GenUDPSt++;
                }
            }            else
            {
                GenUDPSt = SM_HOME;
            }            break;        case SM_UDPPUT:            if (TickGet() - startTime < 5*TICK_SECOND)
            {                if (UDPIsPutReady(MySock) > BUFFER_MAX)
                {
                    UDPPutString(ok);
                    UDPFlush();
                    GenUDPSt++;
                }
            }            else
            {
                GenUDPSt = SM_CLOSE;
            }            break;        case SM_UDPGET:            if (TickGet() - startTime < 5*TICK_SECOND)
            {
                udpPackets = UDPIsGetReady(MySock);                if (udpPackets >= BUFFER_MAX)
                {
                   UDPGetArray(frameBuffer, BUFFER_MAX);
                   UDPDiscard();                   if (frameBuffer[0] == STX && frameBuffer[BUFFER_MAX - 1] == ETX)
                   {
                    Uart_Putc('.');                    for(i=0;i= BUFFER_MAX)
                {
                    UDPPutArray(frameBuffer, BUFFER_MAX);
                    UDPFlush();
                }
                startTime = TickGet();
                GenUDPSt = SM_UDPGET;
            }            else
            {
                printf("xx");      // for debug
                GenUDPSt = SM_CLOSE;
            }            break;        case SM_CLOSE:
            printf("done\r\n");        // for debug            UDPClose(MySock);
            MySock = INVALID_UDP_SOCKET;
            GenUDPSt = SM_HOME;
            TRISCSET = 0x2000; // RC13 Input
            LATCCLR = 0x6000;  // Clear LATC 
            LATHCLR = (1<<2);
            TRISHSET = (1<<2);
            INTDisableInterrupts();
            T1CON = 0;
            ETHCON1 = 0;
            ETHCON2 = 0;
            CoreT_DelayMs(1);
            U1MODE = 0x0;
            U1STA = 0x0;
            (*((void(*)(void))USER_APP_RESET_ADDRESS))();            break;
        }

　　如何使用PhnLoader_v3.0和PhnBoot_v3.0

      1. 使用XC32编译PhnBoot_v3.0（编译前，需先修改linker script）。

　　2. 使用pickit3烧录PhnBoot_v3.0的Hex文件到目标板中。

　　3. 拔除pickit3烧录器

　　4. 连接目标板和PC到同一局域网，设置PC的IP地址，打开PhnLoader_v3.0，选择UDP协议，端口号，IP地址。

　　5. 点击PhnLoader_v3.0用户界面上的“.."按钮加载需要烧录的应用程序Hex文件（编译前，需先修改linker script）

　　6. 重启目标板，等到LED3 灯亮了，立刻在PhnLoader_v3.0界面上点击Download按钮。如果超时未点击Download按钮，会自动跳转到上次烧录的应用程序中去。

　　7. 烧录完毕，再次重启目标板, 数秒后目标板开始正常运行应用程序。

　　之后每次更新应用程序，只需重复步骤 4 ~ 7 就可以了。注意，整个烧录过程未能实现User ID/Configuration Bits的烧写，所以需要保持应用程序的Configuration Bits和Bootloader的Configuration Bits一致。