TCP/IP Stack

　　Microchip TCP/IP Stack是免費(fèi)的，廣泛應(yīng)用于PIC單片機(jī)中。由于有遠(yuǎn)程更新程序的需求，我決定開發(fā)基于TCP協(xié)議的ethernet bootloader, 主要使用了Microchip TCP/IP Stack的TCP模塊。最終我開發(fā)出來的ethernet bootloader 在PIC18F97J60上驗(yàn)證通過。整個(gè)實(shí)現(xiàn)上分兩部分，一部分是單片機(jī)端的基于TCP協(xié)議的bootloader程序，我將其命名為PhnBoot_v2.0, 另外一部分是同樣基于TCP協(xié)議與單片機(jī)互動的PC端通信程序，我將其命名為PhnLoader_v2.0。我還定義了PhnBoot_v2.0和PhnLoader_v2.0之間傳輸數(shù)據(jù)的通信協(xié)定。下面將細(xì)說我是如何實(shí)現(xiàn)的。

　　通信協(xié)定

　　單片機(jī)端PhnBoot_v2.0和PC端PhnLoader_v2.0之間的通信數(shù)據(jù)包采用以下協(xié)定

...

　　定義如下:

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 24 bits ( ADDRL , ADDRH , ADDRH)

　　具體有以下Base command:

RD-VER: 0x00 -- Read Version Information (最終版本刪除了此命令)

RD_MEM： 0x01 -- Read Program Memory (最終版本刪除了此命令)

ER_MEM: 0x03 -- Erase Program Memory

WR_MEM： 0x02 -- Write Program Memory

WR_CFG： 0x04 -- Write Configuration Registers

　　PhnLoader_v2.0 功能

　　定義好了通訊協(xié)定, 接著就按照協(xié)定去實(shí)現(xiàn)PhnLoader_v2.0。 PhnLoader_v2.0的具體功能包括選擇IP地址，端口和協(xié)議類型, 目前只支持TCP協(xié)議, 創(chuàng)建TCP服務(wù)器，加載應(yīng)用程序Hex文件，Parse 應(yīng)用程序的Hex文件，一行一行解讀Hex文件，一旦收到連接請求，建立TCP連接，一旦收到應(yīng)用程序更新請求，立刻按照通訊協(xié)定采用TCP協(xié)議發(fā)送Hex記錄到單片機(jī)，接收單片機(jī)發(fā)送回來的Response，發(fā)送完畢后斷開TCP連接，發(fā)送期間出現(xiàn)問題就立馬結(jié)束發(fā)送。

　　PhnLoader_v2.0 主要代碼段

　　PhnLoader_v2.0是用C#實(shí)現(xiàn)的，是我在利用空余時(shí)間自學(xué)C#后寫的，上面提到的功能都實(shí)現(xiàn)了。

private void btnDownload_Click(object sender, EventArgs e)

{

btnDownload.Enabled = false;

pBarLoading.Visible = false;

if (!this.connect())

{

Debug.WriteLine("Udp server building unsuccessfully");

textBoxStatus.ForeColor = Color.Red;

textBoxStatus.AppendText("Udp server building unsuccessfullyrn");

textBoxStatus.ForeColor = Color.Black;

btnDownload.Enabled = true;

return;

}

try

{

loaderReader = new StreamReader(textBoxFile.Text);

}

catch (Exception ex)

{

Debug.WriteLine("Error: " + ex.Message);

textBoxStatus.ForeColor = Color.Red;

textBoxStatus.AppendText("Read hex file unsuccessfullyrn");

textBoxStatus.ForeColor = Color.Black;

loaderReader.Close();

loaderServer.Close();

btnDownload.Enabled = true;

return;

}

loaderFrame = new SerialFrame();

DateTime startTime = DateTime.Now;

IPEndPoint clientPoint = new IPEndPoint(IPAddress.Any, 0);

if (!loaderServer.Read(readyMsg,timeSpan))

{

Debug.WriteLine("Error: Timeout receive ready message from bootloader");

textBoxStatus.ForeColor = Color.Red;

textBoxStatus.AppendText("Timeout receive ready message from bootloaderrn");

textBoxStatus.ForeColor = Color.Black;

loaderServer.Close();

loaderReader.Close();

btnDownload.Enabled = true;

return;

}

if (!erase())

{

textBoxStatus.ForeColor = Color.Red;

textBoxStatus.AppendText("Erase unsuccessfullyrn");

textBoxStatus.ForeColor = Color.Black;

loaderReader.Close();

loaderServer.Close();

btnDownload.Enabled = true;

return;

}

pBarLoading.Refresh();

pBarLoading.Visible = true;

pBarLoading.Value = 0;

pBarLoading.Maximum = loaderLines;

pBarLoading.Step = 1;

string recordLine;

Address_U = 0;

bool isNextLineUserID = false;

bool isNextLineConfigBits = false;

textBoxStatus.AppendText("rnDownloading hex file ...rn");

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);

Address_U = 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);

Address_U = Convert.ToInt32(addrU, 16) << 16;