Link Status Callback

Functions
void	link_status (uint8_t mode)
	link status change callback function More...
uint16_t	monitor_link_status (tpOutputFunc pLog)
	monitor link status change More...
uint16_t	monitor_ip_address (tpOutputFunc pLog)
	monitor IP assignment More...

Detailed Description

The link status callback function is called from net_isq() any time the link status has changed. Use this function to print a message, switch LED's, set global variables (e.g. _link) to enable/ disable specific sections of code.

Install this callback by passing this function as parameter to DM2_EmacInit() during initialization.

You shouldn't make use of long operation functions (like stdio printf) within this callback. Use global flags instead.

In case of DHCP configuration the internal IP address should be reset, if no link is available and the DHCP request should be re-triggered if a link is established. Optionally the ARP cache can be cleared (arp_clear_cache()) to avoid long response times if a destination route has changed.

Function Documentation

void link_status

(

uint8_t

mode

)

Parameters

mode	- HDX_10, HDX_100, FDX_10, FDX_100, FDX1000

Returns

nothing

See also

DM2_EmacInit

Hardware Initialization, _link, BoardSpecific.c

HDX_10, HDX_100, FDX_10, FDX_100, FDX_1000

Examples:

BoardSpecific.c.

{
   _link_mode = mode;
    switch (mode)
    {
        case 0xff:
            /*******************************************************************
             reset global link status
            *******************************************************************/
            _link = 0;

            /*******************************************************************
             in case of DHCP reset IP address
            *******************************************************************/
            if (!((eth.ip[0]-'0')<=9))
            {
                set_ip_address (0, "0.0.0.0");
            }
            break;

        default:
            /*******************************************************************
             set global link status
            *******************************************************************/
            _link |= 1;

            /*******************************************************************
             clear ARP cache
            *******************************************************************/
            arp_clear_cache();

            /*******************************************************************
             in case of DHCP re-trigger DHCP request
            *******************************************************************/
            if ((!((eth.ip[0]-'0')<=9)) && eth.dhcp_setting)
            {
                eth.dhcp_setting (eth.ip, 0);
            }
            break;
    }
}

uint16_t monitor_link_status

(

tpOutputFunc

pLog

)

Parameters

pLog	- printf function or NULL

Returns

TRUE (1) - link status changed

FALSE (0) - link status not changed

Use this function in your main loop to detect a link status change. Global flag _link_mode is monitored and in case of change a LED can be toggled or a message can be printed on the default output terminal. Parameter pLog can be a standard formatted print function like printf or CPrintf. If this parameter is NULL, no output is printed. The return value can be used for event processing in case of a status change.

Note

_link_mode is only valid, if a link_status callback function is used and the _link_mode is set.

See also

DHCPTest.c

Examples:

BoardSpecific.c.

{
    /***************************************************************************
     locals
    ***************************************************************************/
    static uint8_t _link_mode_old = 0xff;

    if (_link_mode_old != _link_mode)
    {
        _link_mode_old = _link_mode;
        if (pLog) pLog ("\n\r Link status changed: ");
        switch (_link_mode)
        {
            case 0xff:
                LED_off (2);
                if (pLog) pLog ("No Link\r\n");
                break;

            default:
                LED_on (2);
                if (pLog) pLog ("Linked at %d%sMbit %s duplex\r\n",
                        (_link_mode & SPEED_100) ? 100:10,
                        (_link_mode & SPEED_1000) ? "00 ":" ",
                        (_link_mode & FULL_DUPLEX) ? "full":"half");
                break;
        }
        return (1);
    }
    return (0);
}

uint16_t monitor_ip_address

(

tpOutputFunc

pLog

)

Parameters

pLog	- printf function or NULL

Returns

TRUE (1) - IP address assigned

FALSE (0) - IP address not changed

Use this function to monitor IP assignment. Useful when the IP address is assigned dynamically by DHCP. The return value can be used for event processing, e.g. send a welcome message or email. Parameter pLog can be a standard formatted print function like printf or CPrintf. If this parameter is NULL, no output is printed.

See also

DHCPTest.c

Examples:

BoardSpecific.c.

{
    /***************************************************************************
      locals
    ***************************************************************************/
    static uint16_t wait_for_ip = 1;
    uint16_t ret = 0;
    uint32_t ip;

    /***************************************************************************
      try to detect IP assignment
    ***************************************************************************/
    if ((ip=get_ip_address (0)) == UINT32_C(0))  // no IP address assigned
    {
        wait_for_ip = 1;
        return(ret);
    }

    if (wait_for_ip)
    {
        wait_for_ip = 0;
        ret = 1;

        if (pLog)
        {
            if (IS_LINKLOCAL(ip))
            {
                pLog (" !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!\r\n");
                pLog (" !!! warning: no DHCP server available           !!!\r\n");
                pLog (" !!! assigned IP address is a link-local address !!!\r\n");
                pLog (" !!! make sure your host is in the same local    !!!\r\n");
                pLog (" !!! subnet: 169.254.x.x                         !!!\r\n");
                pLog (" !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!\r\n");
            }

            pLog ("\r\n network configuration:");
            net_print_stat (0, pLog);
        }
    }

    return (ret);
}