rs232d/rs232d.c

Simple RS232 server. Use a serial cable to connect the RS232 port of the Ethernut Board with a COM port of a PC. Start a terminal program and a telnet client on the PC. Telnet should connect to the Ethernut Board.

Characters typed in the telnet window will appear in the terminal program window and vice versa. Baudrate is 9600.

#include <dev/board.h>

#include <sys/heap.h>
#include <sys/thread.h>
#include <sys/timer.h>
#include <sys/socket.h>

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <io.h>
#include <fcntl.h>

#include <arpa/inet.h>

#include <pro/dhcp.h>

#define BUFFERSIZE  128
#define TCPPORT     23

typedef struct {
    FILE *cd_rs232;
    FILE *cd_tcpip;
    char cd_connected;
} CHANNEL;

/*
 * Transfer data from input stream to output stream.
 */
void StreamCopy(FILE * istream, FILE * ostream, char *cop)
{
    int cnt;
    char *buff;

    buff = malloc(BUFFERSIZE);
    while (*cop) {
        if ((cnt = fread(buff, 1, BUFFERSIZE, istream)) <= 0)
            break;
        if (*cop && (cnt = fwrite(buff, 1, cnt, ostream)) <= 0)
            break;
        if (*cop && fflush(ostream))
            break;
    }
    *cop = 0;
    free(buff);
}

/*
 * From RS232 to socket.
 */
THREAD(Receiver, arg)
{
    CHANNEL *cdp = arg;

    for (;;) {
        if (cdp->cd_connected) {
            NutThreadSetPriority(64);
            /*
             * We are reading from the UART without any timeout. So we
             * won't return immediately when disconnected.
             */
            StreamCopy(cdp->cd_rs232, cdp->cd_tcpip, &cdp->cd_connected);
            NutThreadSetPriority(128);
        }
        NutThreadYield();
    }
}

/*
 * Main application routine. 
 *
 * Nut/OS automatically calls this entry after initialization.
 */
int main(void)
{
    TCPSOCKET *sock;
    CHANNEL cd;
    u_long baud = 9600;

    /*
     * Register our devices.
     */
    NutRegisterDevice(&DEV_UART, 0, 0);
    NutRegisterDevice(&DEV_ETHER, 0x8300, 5);

    /*
     * Setup the uart device.
     */
    cd.cd_rs232 = fopen(DEV_UART_NAME, "r+b");
    _ioctl(_fileno(cd.cd_rs232), UART_SETSPEED, &baud);

    /*
     * Setup the ethernet device. Try DHCP first. If this is
     * the first time boot with empty EEPROM and no DHCP server
     * was found, use hardcoded values.
     */
    if (NutDhcpIfConfig(DEV_ETHER_NAME, 0, 60000)) {
        /* No valid EEPROM contents, use hard coded MAC. */
        u_char my_mac[] = { 0x00, 0x06, 0x98, 0x20, 0x00, 0x00 };

        if (NutDhcpIfConfig("eth0", my_mac, 60000)) {
            /* No DHCP server found, use hard coded IP address. */
            u_long ip_addr = inet_addr("192.168.192.100");
            u_long ip_mask = inet_addr("255.255.255.0");

            NutNetIfConfig("eth0", my_mac, ip_addr, ip_mask);
            /* If not in a local network, we must also call 
               NutIpRouteAdd() to configure the routing. */
        }
    }

    /*
     * Start a RS232 receiver thread.
     */
    NutThreadCreate("xmit", Receiver, &cd, 512);

    /*
     * Now loop endless for connections.
     */
    cd.cd_connected = 0;
    for (;;) {
        /*
         * Create a socket and listen for a client.
         */
        sock = NutTcpCreateSocket();
        NutTcpAccept(sock, TCPPORT);

        /*
         * Open a stdio stream assigned to the connected socket.
         */
        cd.cd_tcpip = _fdopen((int) sock, "r+b");
        cd.cd_connected = 1;

        /*
         * Call RS232 transmit routine. On return we will be
         * disconnected again.
         */
        StreamCopy(cd.cd_tcpip, cd.cd_rs232, &cd.cd_connected);

        /*
         * Close the stream.
         */
        fclose(cd.cd_tcpip);

        /*
         * Close our socket.
         */
        NutTcpCloseSocket(sock);
    }
}

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