EMAC_PHY_FORCE_100B_T_HALF_DUPLEX doesn't actually disable auto negotiation.

I am working on a new feature for a firmware product based on the TM4C MCU. The feature is the ability to disable auto-negotiation and set the speed and duplex statically.

After reading the documentation (Tiva C Series TM4C129x Users Guide page 126). It states that if I use any of these values:

EMAC_PHY_FORCE_10B_T_HALF_DUPLEX

EMAC_PHY_FORCE_10B_T_FULL_DUPLEX

EMAC_PHY_FORCE_100B_T_FULL_DUPLEX

EMAC_PHY_FORCE_100B_T_HALF_DUPLEX

It will disable auto-negotiation and set the speed and duplex statically. However after testing this I am finding that it doesn't actually do that.

An auto-negotiation cycle is still initialized by lwip and the speed and duplex are set to the desired values, but with auto-negotiation enabled.

Code Sample:

Here are the defines for each of 5 options that the customer wants:

#define EMAC_PHY_CONFIG (EMAC_PHY_TYPE_INTERNAL | EMAC_PHY_INT_MDIX_EN | \
EMAC_PHY_AN_100B_T_FULL_DUPLEX)

#define EMAC_PHY_CONFIG_100_FULL (EMAC_PHY_TYPE_INTERNAL | EMAC_PHY_INT_MDIX_EN | \
EMAC_PHY_FORCE_100B_T_FULL_DUPLEX)

#define EMAC_PHY_CONFIG_100_HALF (EMAC_PHY_TYPE_INTERNAL | EMAC_PHY_INT_MDIX_EN | \
EMAC_PHY_FORCE_100B_T_HALF_DUPLEX)

#define EMAC_PHY_CONFIG_10_FULL (EMAC_PHY_TYPE_INTERNAL | EMAC_PHY_INT_MDIX_EN | \
EMAC_PHY_FORCE_10B_T_FULL_DUPLEX)

#define EMAC_PHY_CONFIG_10_HALF (EMAC_PHY_TYPE_INTERNAL | EMAC_PHY_INT_MDIX_EN | \
EMAC_PHY_FORCE_10B_T_HALF_DUPLEX)

Here is the initialization code that I placed in lwip (network_config is a struct that is read from flash memory before this function is executed which contains the user's desired settings)

void
lwIPInit(uint32_t ui32SysClkHz, const uint8_t *pui8MAC, struct ip_addr ui32IPAddr, struct ip_addr ui32NetMask, struct ip_addr ui32GWAddr, uint32_t ui32IPMode)
{
    // Check the parameters.
#if LWIP_DHCP && LWIP_AUTOIP
    ASSERT((ui32IPMode == IPADDR_USE_STATIC) || (ui32IPMode == IPADDR_USE_DHCP) || (ui32IPMode == IPADDR_USE_AUTOIP));
#elif LWIP_DHCP
    ASSERT((ui32IPMode == IPADDR_USE_STATIC) || (ui32IPMode == IPADDR_USE_DHCP));
#elif LWIP_AUTOIP
    ASSERT((ui32IPMode == IPADDR_USE_STATIC) || (ui32IPMode == IPADDR_USE_AUTOIP));
#else
    ASSERT(ui32IPMode == IPADDR_USE_STATIC);
#endif

    // Enable the ethernet peripheral.
    MAP_SysCtlPeripheralEnable(SYSCTL_PERIPH_EMAC0);
    MAP_SysCtlPeripheralReset(SYSCTL_PERIPH_EMAC0);

    // Enable the internal PHY if it's present and we're being asked to use it.
    if((EMAC_PHY_CONFIG & EMAC_PHY_TYPE_MASK) == EMAC_PHY_TYPE_INTERNAL)
    {
        // We've been asked to configure for use with the internal PHY.  Is it present?
        if(MAP_SysCtlPeripheralPresent(SYSCTL_PERIPH_EPHY0))
        {
            // Yes - enable and reset it.
            MAP_SysCtlPeripheralEnable(SYSCTL_PERIPH_EPHY0);
            MAP_SysCtlPeripheralReset(SYSCTL_PERIPH_EPHY0);
        }
        else
        {
            // Internal PHY is not present on this part so hang here.
            while(1)
            {
            	debug_printf("No PHY!?\r\n");
            }
        }
    }

    // Wait for the MAC to come out of reset.
    while(!MAP_SysCtlPeripheralReady(SYSCTL_PERIPH_EMAC0)) {}

    if (network_config.auto_neg)
    {
       // Configure for use with whichever PHY the user requires.
       MAP_EMACPHYConfigSet(EMAC0_BASE, EMAC_PHY_CONFIG);
       debug_printf("Auto Negotiation Enabled\t\n");
    }
    else if (!network_config.auto_neg)
    {
    	if (network_config.full_duplex)
    	{
    		debug_printf("Link Duplex:Full\t\n");
    		if (network_config.full_speed)
    		{
    			MAP_EMACPHYConfigSet(EMAC0_BASE, EMAC_PHY_CONFIG_100_FULL);
    			debug_printf("Link Speed:100 Mbps\t\n");
    		}
    		else
    		{
    			MAP_EMACPHYConfigSet(EMAC0_BASE, EMAC_PHY_CONFIG_10_FULL);
    			debug_printf("Link Speed:10 Mbps\t\n");
    		}
    	}
    	else
    	{
    		debug_printf("Link Duplex:Half\t\n");
    		if (network_config.full_speed)
    		{
    			MAP_EMACPHYConfigSet(EMAC0_BASE, EMAC_PHY_CONFIG_100_HALF);
    			debug_printf("Link Speed:100 Mbps\t\n");
    		}
    		else
    		{
    			MAP_EMACPHYConfigSet(EMAC0_BASE, EMAC_PHY_CONFIG_10_HALF);
    			debug_printf("Link Speed:10 Mbps\t\n");
    		}
    	}
    }



    // Initialize the MAC and set the DMA mode.
    MAP_EMACInit(EMAC0_BASE, ui32SysClkHz, EMAC_BCONFIG_MIXED_BURST | EMAC_BCONFIG_PRIORITY_FIXED, 4, 4, 0);

    // Set MAC configuration options.
    MAP_EMACConfigSet(EMAC0_BASE, (EMAC_CONFIG_FULL_DUPLEX |
                                   EMAC_CONFIG_CHECKSUM_OFFLOAD |
                                   EMAC_CONFIG_7BYTE_PREAMBLE |
                                   EMAC_CONFIG_IF_GAP_96BITS |
                                   EMAC_CONFIG_USE_MACADDR0 |
                                   EMAC_CONFIG_SA_FROM_DESCRIPTOR |
                                   EMAC_CONFIG_BO_LIMIT_1024),
                      (EMAC_MODE_RX_STORE_FORWARD |
                       EMAC_MODE_TX_STORE_FORWARD |
                       EMAC_MODE_TX_THRESHOLD_64_BYTES |
                       EMAC_MODE_RX_THRESHOLD_64_BYTES), 0);

    // Program the hardware with its MAC address (for filtering).
    MAP_EMACAddrSet(EMAC0_BASE, 0, (uint8_t *)pui8MAC);

    // Save the network configuration for later use by the private initialization.
    g_ui32IPMode = ui32IPMode;
    g_ui32IPAddr = ui32IPAddr;
    g_ui32NetMask = ui32NetMask;
    g_ui32GWAddr = ui32GWAddr;

    // Initialize lwIP.
    // The remainder of initialization is done immediately if not using a RTOS and it is deferred to the TCP/IP thread's context if using a RTOS.
#if NO_SYS
    lwIPPrivateInit(0);
#else
    tcpip_init(lwIPPrivateInit, 0);
#endif
}

Any help on this would be great. I really wish these settings were a little more straight forward, I searched Google and the TI forms for any information about this and I came up with very little.

Thanks,

Jonathan L Clark