TFTP is a simple file transfer protocol. I am not too embarrassed about the protocol. For those interested, please refer to RFC1350:https://tools.ietf.org/html/rfc1350    

This example shows that the lower computer runs LWIP as the TFTP server and the Windows side as the client.

1. Windows send files to the lower computer
2. Get files from the lower machine

 

The LWIP package is perfect, TFTP is very convenient to use. Open the tftp_server.h file and you only need to write four callback functions, namely:

• open a file
• Close file
• data input
• Read data

Tftp_server.h as shown:

Of course, there is still one pit, and things are not as smooth as imagined. The author easily implemented the file transmission during debugging, but the file acquisition failed.

According to the description of tftp_server.h above, the read function written by the author returns 0 when the read succeeds, and the result of obtaining the file fails. Later, comparing the official API, I found that the tftp_server.h I downloaded is garbled. As shown in the following figure, the return value is >=0, which is successful, not =0.The final simulation confirms that you need to return the number of bytes read.. Think about it, or you can't know the file size.

 

The following attached code:

 

//tftp
struct tftp_context mytftp;

typedef struct
{
	uint8_t isOpenOK;
	Uint8_t type;//0:GCode 1: Cache GCode 2: Firmware
	uint8_t write;
	char name[64];
}TFTP_Handler;
TFTP_Handler tftp_Handler;

void* TFTP_Open(const char* fname, const char* mode, u8_t write)
{
	uint8_t res;
	char name[64];
	tftp_Handler.write=write;
	
	tftp_Handler.type=0;
	strcpy(name,"0:");
	strcat(name,fname);
	
	if(write)
	{
		res=f_open(file,name,FA_CREATE_ALWAYS|FA_WRITE);
	}
	else
	{
		res=f_open(file,name,FA_OPEN_EXISTING|FA_READ);
	}
	tftp_Handler.isOpenOK=res;
	return &tftp_Handler;
}
void TFTP_Close(void* handle)
{
	uint8_t res=0;
	 
	if(((TFTP_Handler*)handle)->isOpenOK)
		return;
	f_close(file);
	printf("Transfer file completed!\r\n");
}
int TFTP_Read(void* handle, void* buf, int bytes)
{
	uint8_t res;
	res=((TFTP_Handler*)handle)->isOpenOK;
	if(res)return -1;
	res = f_read(file,(uint8_t*)buf,bytes,&br);

	printf("Read File:%d  Len:%d  br:%d\r\n",res,bytes,br);
	return br;
}
int TFTP_Write(void* handle, struct pbuf* p)
{
	uint8_t res;
	res=((TFTP_Handler*)handle)->isOpenOK;
	if(res)return -1;
	res = f_write(file,p->payload,p->len,&bw);

	printf("Write File:%d  Len:%d  bw:%d\r\n",res,p->len,bw);
	return 0;
}
void TFTP_ContextInit()
{
	mytftp.open=TFTP_Open;
	mytftp.close=TFTP_Close;
	mytftp.read=TFTP_Read;
	mytftp.write=TFTP_Write;
}

 

Finally, there are two ways to debug Windows:

• Using a command prompt

Send and get:

Compare it:

description:

• Using debugging software