1. 1 Lab. 6 Communication Between DSP and PC  OSI seven layers:  App –HTTP –FTP  Transport –TCP –UDP  Network –IP  Data Link –EMAC  Physical –PHY * DSP accesses the Ethernet via the ethernet media access controller (EMAC) component.

2. 2  The network app has two pieces –Server –Client  Server –Provide requested service to client –Send requested data (e.g. http - web page)  Client –Request service and data from server  TCP –Allow handshaking between the client and server and therefore guarantees the correct delivery of information.  UDP –Do not implement handshaking (therefore, it is unreliable) but has an overall reduced communications overhead (thus, a bit faster).

3. 3  IP Address –a unique logical address used to identify and communicate over on a computer network (a computer address)  Port Number –a special number present in the header of a data packet used to map data to a process. –IP = city block –port = house number.  A socket is the interface between the application code and the TCP/IP stack.  It is an intelligent buffer that contains information regarding a connection. –For example, the FTP application is using port “x” at IP address “y” and is currently active. The socket also contains pointers to where the data is stored.

4. 4  Socket:

5. 5  UDP socket programming API:

6. 6  Sample codes: –Transmit the data in a file from PC to DSP and then DSP transmit the data back to PC and store them in another file. –helloWord.c/board2.c for DSP –TRX.m for PC  PC IP for DSP to recognize: –(in PC) 控制台  網路連線  區域連線 ( 內容 )  TCP/IP ( 內 容 )  IP 192.168.0.40 、預設閘道 192.168.0.1  DSP IP for PC recognize: –char *LocalIPAddr = "192.168.0.39"; (helloWord.c/L72)  PC IP for DSP to transmit: –char *UnicastAddr = "192.168.0.40"; (board2.c/L19)

7. 7  Transmit port for DSP: –to.sin_port = htons(5000); (board2.c/L73)  Receive port for PC: –v = udp('192.168.0.39', 'LocalPort',5000,……); (TRX.m)  Receive port for DSP: –rec.sin_port = htons(100); (board2.c/L51)  Transmit port for PC: –u = udp('192.168.0.39','RemotePort',100,……);(TRX.m)  helloWorld.c will call the function board2.c and your codes are put in board2.c –Start from L90  Transmit unit –#define size 256 (board2.c/L8, the number of bytes)

8. 8  Define data type (board L12) - Transmit characters  Send/receive:  Run the DSP codes first. union mydata { float myval; char char_val[4]; }; union mydata Send_Buf[size]; union mydata Recv_Buf[size]; recvfrom(recv, &Recv_Buf[0].char_val[0], size*4, 0, (struct sockaddr*)&rec, &sz ); sendto(send, &Send_Buf[0].char_val[0], size*4, 0, (struct sockaddr *)&to, sizeof(to));

9. 9  Then, run the codes in PC –Run the TRX.m matlab code  Practice 1: –Run the sample codes and check if the results are OK.  Practice 2: –Use Matlab to generate a sequence and write the result to a file. –Use Matlab to read data in the file and check if the result is OK.

10. 10  With Matlab: –Create 2 udp sockets, one for transmission and the other for receiving. –The default buffer size is 128 –Use fwrite and fread to do transmission and receiving. fwrite(u,TX_buffer,'float'); temp = fread(v,size,'float'); –Close and clear the sockers

11. 11  Practice 3: –Modify the codes such that you can conduct the FFT of a sequence (stored in a file of PC) with DSP and send the magnitude response back to the PC (stored in another file). –Use Matlab to generate the sequence and write the result in a file. –Use Matlab to open the file wrote by DSP and check if the result is OK.