以太网 - ESP32 - — ESP-IDF 编程指南 v5.2.2 文档

以太网基本概念 

以太网是一种异步的带冲突检测的载波侦听多路访问 (CSMA/CD) 协议/接口。通常来说，以太网不太适用于低功率应用。然而，得益于其广泛的部署、高效的网络连接、高数据率以及范围不限的可扩展性，几乎所有的有线通信都可以通过以太网进行。

符合 IEEE 802.3 标准的正常以太网帧的长度在 64 至 1518 字节之间，由五个或六个不同的字段组成：目的地 MAC 地址 (DA)、源 MAC 地址 (SA)、类型/长度字段、数据有效载荷字段、可选的填充字段和帧校验序列字段 (CRC)。此外，在以太网上传输时，以太网数据包的开头需附加 7 字节的前导码和 1 字节的帧起始符 (SOF)。

因此，双绞线上的通信如图所示：

以太网数据帧格式 

前导码和帧起始符 

前导码包含 7 字节的 55H ，作用是使接收器在实际帧到达之前锁定数据流。

帧前界定符 (SFD) 为二进制序列 10101011 （物理介质层可见）。有时它也被视作前导码的一部分。

在传输和接收数据时，协议将自动从数据包中生成/移除前导码和帧起始符。

目的地址 (DA) 

目的地址字段包含一个 6 字节长的设备 MAC 地址，数据包将发送到该地址。如果 MAC 地址第一个字节中的最低有效位是 1，则该地址为组播地址。例如，01-00-00-F0-00 和 33-45-67-89-AB-CD 是组播地址，而 00-00-00-F0-00 和 32-45-67-89-AB-CD 不是。

带有组播地址的数据包将到达选定的一组以太网节点，并发挥重要作用。如果目的地址字段是保留的多播地址，即 FF-FF-FF-FF-FF-FF，则该数据包是一个广播数据包，指向共享网络中的每个对象。如果 MAC 地址的第一个字节中的最低有效位为 0，则该地址为单播地址，仅供寻址节点使用。

通常，EMAC 控制器会集成接收过滤器，用于丢弃或接收带有组播、广播和/或单播目的地址的数据包。传输数据包时，由主机控制器将所需的目标地址写入传输缓冲区。

源地址 (SA) 

源地址字段包含一个 6 字节长的节点 MAC 地址，以太网数据包通过该节点创建。以太网的用户需为所使用的任意控制器生成唯一的 MAC 地址。MAC 地址由两部分组成：前三个字节称为组织唯一标识符 (OUI)，由 IEEE 分配；后三个字节是地址字节，由购买 OUI 的公司配置。有关 ESP-IDF 中使用的 MAC 地址的详细信息，请参见 MAC 地址分配。

传输数据包时，由主机控制器将分配的源 MAC 地址写入传输缓冲区。

类型/长度 

类型/长度字段长度为 2 字节。如果其值 <= 1500（十进制），则该字段为长度字段，指定在数据字段后的非填充数据量；如果其值 >= 1536，则该字段值表示后续数据包所属的协议。以下为该字段的常见值：

IPv4 = 0800H

IPv6 = 86DDH

ARP = 0806H

使用专有网络的用户可以将此字段配置为长度字段。然而，对于使用互联网协议 (IP) 或地址解析协议 (ARP) 等协议的应用程序，在传输数据包时，应将此字段配置为协议规范定义的适当类型。

数据有效载荷 

数据有效载荷字段是一个可变长度的字段，长度从 0 到 1500 字节不等。更大的数据包会因违反以太网标准而被大多数以太网节点丢弃。

数据有效载荷字段包含客户端数据，如 IP 数据报。

填充及帧校验序列 (FCS) 

填充字段是一个可变长度的字段。数据有效载荷较小时，将添加填充字段以满足 IEEE 802.3 规范的要求。

以太网数据包的 DA、SA、类型、数据有效载荷和填充字段共计必须不小于 60 字节。加上所需的 4 字节 FCS 字段，数据包的长度必须不小于 64 字节。如果数据有效载荷字段小于 46 字节，则需要加上一个填充字段。

帧校验序列字段 (FCS) 长度为 4 字节，其中包含一个行业标准的 32 位 CRC，该 CRC 是根据 DA、SA、类型、数据有效载荷和填充字段的数据计算的。鉴于计算 CRC 的复杂性，硬件通常会自动生成一个有效的 CRC 进行传输。否则，需由主机控制器生成 CRC 并将其写入传输缓冲区。

通常情况下，主机控制器无需关注填充字段和 CRC 字段，因为这两部分可以在传输或接收时由硬件 EMAC 自动生成或验证。然而，当数据包到达时，填充字段和 CRC 字段将被写入接收缓冲区。因此，如果需要的话，主机控制器也可以对它们进行评估。

除了上述的基本数据帧，在 10/100 Mbps 以太网中还有两种常见的帧类型：控制帧和 VLAN 标记帧。ESP-IDF 不支持这两种帧类型。

MII 和 RMII 的一个明显区别在于其所需的信号数。MII 通常需要多达 18 个信号，RMII 接口则仅需要 9 个信号。

在 RMII 模式下，接收器和发射器信号的参考时钟为 REF_CLK 。 在访问 PHY 和 MAC 时，REF_CLK 必须保持稳定 。一般来说，根据设计中 PHY 设备的特征，可通过以下三种方式生成 REF_CLK ：

一些 PHY 芯片可以从其外部连接的 25 MHz 晶体振荡器中获取 REF_CLK （如图中的选项 a 所示）。对于此类芯片，请在 CONFIG_ETH_RMII_CLK_MODE 中选择 CONFIG_ETH_RMII_CLK_INPUT 。

一些 PHY 芯片使用可以作为 MAC 端 REF_CLK 的外接 50 MHz 晶体振荡器或其他时钟源（如图中的选项 b 所示）。对于此类芯片，请同样在 CONFIG_ETH_RMII_CLK_MODE 中选择 CONFIG_ETH_RMII_CLK_INPUT 。

一些 EMAC 控制器可以使用其内部的高精度 PLL 生成 REF_CLK （如图中的选项 c 所示）。此种情况下，请在 CONFIG_ETH_RMII_CLK_MODE 中选择 CONFIG_ETH_RMII_CLK_OUTPUT 。

如上所述， REF_CLK 默认通过项目配置进行配置。然而，通过设置 eth_esp32_emac_config_t::interface 和 eth_esp32_emac_config_t::clock_config ，也可以实现在用户应用代码中覆盖该时钟。更多细节，请参见 emac_rmii_clock_mode_t 和 emac_rmii_clock_gpio_t 。

如果配置 RMII 时钟模式为 CONFIG_ETH_RMII_CLK_OUTPUT ，那么就可以使用 GPIO0 输出 REF_CLK 信号。更多细节，请参见 CONFIG_ETH_RMII_CLK_OUTPUT_GPIO0 。

值得一提的是，如果设计中并未使用 PSRAM，则 GPIO16 和 GPIO17 也可以用来输出参考时钟。更多细节，请参见 CONFIG_ETH_RMII_CLK_OUT_GPIO 。

如果配置 RMII 时钟模式为 CONFIG_ETH_RMII_CLK_INPUT ，那么有且只有 GPIO0 可以用来输入 REF_CLK 信号。请注意， GPIO0 同时也是 ESP32 上一个重要的 strapping GPIO 管脚。如果 GPIO0 在上电时采样为低电平，ESP32 将进入下载模式，需进行手动复位重启系统。解决这个问题的方法是，在硬件中默认禁用 REF_CLK ，从而避免 strapping 管脚在启动阶段受到其他信号的干扰。随后，再在以太网驱动安装阶段重新启用 REF_CLK 。

可以通过以下方法禁用 REF_CLK 信号：

禁用或关闭晶体振荡器的电源（对应图中的选项 b ）。

强制复位 PHY 设备（对应图中的选项 a ）。 此种方法并不适用于所有 PHY 设备 ，即便处于复位状态，某些 PHY 设备仍会向 GPIO0 输出信号。

无论选择哪种 RMII 时钟模式，都请确保硬件设计中 REF_CLK 的信号完整性！ 信号线越短越好，并请保持信号线与 RF 设备和电感器元件的距离。

ESP-IDF 只支持 RMII 接口（即在 Kconfig 选项 CONFIG_ETH_PHY_INTERFACE 中始终选择 CONFIG_ETH_PHY_INTERFACE_RMII ）。

在数据平面使用的信号通过 MUX 连接至特定的 GPIO，这些信号无法配置至其他 GPIO。在控制平面使用的信号则可以通过 Matrix 矩阵路由到任何空闲 GPIO。相关的硬件设计示例，请参考 ESP32-Ethernet-Kit 。

根据以太网板设计，需要分别为 MAC 和 PHY 配置必要的参数，通过两者完成驱动程序的安装。

MAC 的相关配置可以在 eth_mac_config_t 中找到，具体包括：

eth_mac_config_t::sw_reset_timeout_ms ：软件复位超时值，单位为毫秒。通常，MAC 复位应在 100 ms 内完成。

eth_mac_config_t::rx_task_stack_size 和 eth_mac_config_t::rx_task_prio ：MAC 驱动会创建一个专门的任务来处理传入的数据包，这两个参数用于设置该任务的堆栈大小和优先级。

eth_mac_config_t::flags ：指定 MAC 驱动应支持的额外功能，尤其适用于某些特殊情况。这个字段的值支持与以 ETH_MAC_FLAG_ 为前缀的宏进行 OR 运算。例如，如果 MAC 驱动应在禁用缓存后开始工作，那么则需要用 ETH_MAC_FLAG_WORK_WITH_CACHE_DISABLE 配置这个字段。

eth_esp32_emac_config_t::smi_mdc_gpio_num 和 eth_esp32_emac_config_t::smi_mdio_gpio_num ：连接 SMI 信号的 GPIO 编号。

eth_esp32_emac_config_t::interface ：配置到 PHY (MII/RMII) 的 MAC 数据接口。

eth_esp32_emac_config_t::clock_config ：配置 EMAC 接口时钟（RMII 模式下的 REF_CLK 模式以及 GPIO 编号）。

PHY 的相关配置可以在 eth_phy_config_t 中找到，具体包括：

eth_phy_config_t::phy_addr ：同一条 SMI 总线上可以存在多个 PHY 设备，所以有必要为各个 PHY 设备分配唯一地址。通常，这个地址是在硬件设计期间，通过拉高/拉低一些 PHY strapping 管脚来配置的。根据不同的以太网开发板，可配置值为 0 到 15 。需注意，如果 SMI 总线上仅有一个 PHY 设备，将该值配置为 -1 ，即可使驱动程序自动检测 PHY 地址。

eth_phy_config_t::reset_timeout_ms ：复位超时值，单位为毫秒。通常，PHY 复位应在 100 ms 内完成。

eth_phy_config_t::autonego_timeout_ms ：自动协商超时值，单位为毫秒。以太网驱动程序会自动与对等的以太网节点进行协商，以确定双工和速度模式。此值通常取决于电路板上 PHY 设备的性能。

eth_phy_config_t::reset_gpio_num ：如果开发板同时将 PHY 复位管脚连接至了任意 GPIO 管脚，请使用该字段进行配置。否则，配置为 -1 。

ESP-IDF 在宏 ETH_MAC_DEFAULT_CONFIG 和 ETH_PHY_DEFAULT_CONFIG 中为 MAC 和 PHY 提供了默认配置。

创建 MAC 和 PHY 实例 

以太网驱动是以面向对象的方式实现的。对 MAC 和 PHY 的任何操作都应基于实例。

内部 EMAC + 外部 PHY 

eth_mac_config_t mac_config = ETH_MAC_DEFAULT_CONFIG();                      // 应用默认的通用 MAC 配置
eth_esp32_emac_config_t esp32_emac_config = 




    
ETH_ESP32_EMAC_DEFAULT_CONFIG(); // 应用默认的供应商特定 MAC 配置
esp32_emac_config.smi_mdc_gpio_num = CONFIG_EXAMPLE_ETH_MDC_GPIO;            // 更改用于 MDC 信号的 GPIO
esp32_emac_config.smi_mdio_gpio_num = CONFIG_EXAMPLE_ETH_MDIO_GPIO;          // 更改用于 MDIO 信号的 GPIO
esp_eth_mac_t *mac = esp_eth_mac_new_esp32(&esp32_emac_config, &mac_config); // 创建 MAC 实例
eth_phy_config_t phy_config = ETH_PHY_DEFAULT_CONFIG();      // 应用默认的 PHY 配置
phy_config.phy_addr = CONFIG_EXAMPLE_ETH_PHY_ADDR;           // 根据开发板设计更改 PHY 地址
phy_config.reset_gpio_num = CONFIG_EXAMPLE_ETH_PHY_RST_GPIO; // 更改用于 PHY 复位的 GPIO
esp_eth_phy_t *phy = esp_eth_phy_new_ip101(&phy_config);     // 创建 PHY 实例
// ESP-IDF 为数种以太网 PHY 芯片驱动提供官方支持
// esp_eth_phy_t *phy = esp_eth_phy_new_rtl8201(&phy_config);
// esp_eth_phy_t *phy = esp_eth_phy_new_lan8720(&phy_config);
// esp_eth_phy_t *phy = esp_eth_phy_new_dp83848(&phy_config);
可选的运行时 MAC 时钟配置
可以通过用户应用程序代码，选择性配置 EMAC 中的 REF_CLK。
eth_esp32_emac_config_t esp32_emac_config = ETH_ESP32_EMAC_DEFAULT_CONFIG(); // 应用默认的供应商特定 MAC 配置
// ...
esp32_emac_config.interface = EMAC_DATA_INTERFACE_RMII;                      // 更改 EMAC 数据接口
esp32_emac_config.clock_config.rmii.clock_mode = EMAC_CLK_OUT;               // 配置 EMAC REF_CLK 模式
esp32_emac_config.clock_config.rmii.clock_gpio = EMAC_CLK_OUT_GPIO;          // 配置用于输入/输出 EMAC REF_CLK 的 GPIO 编号
esp_eth_mac_t *mac = esp_eth_mac_new_esp32(&esp32_emac_config, &mac_config); // 创建 MAC 实例
SPI-Ethernet 模块
eth_mac_config_t mac_config = ETH_MAC_DEFAULT_CONFIG();      // 应用默认的通用 MAC 配置
eth_phy_config_t phy_config = ETH_PHY_DEFAULT_CONFIG();      // 应用默认的 PHY 配置
phy_config.phy_addr = CONFIG_EXAMPLE_ETH_PHY_ADDR;           // 根据开发板设计更改 PHY 地址
phy_config.reset_gpio_num = CONFIG_EXAMPLE_ETH_PHY_RST_GPIO; // 更改用于 PHY 复位的 GPIO
// 安装 GPIO 中断服务（因为 SPI-Ethernet 模块为中断驱动）
gpio_install_isr_service(0);
// 配置 SPI 总线
spi_device_handle_t spi_handle = NULL;
spi_bus_config_t buscfg = {
    .miso_io_num = CONFIG_EXAMPLE_ETH_SPI_MISO_GPIO,
    .mosi_io_num = CONFIG_EXAMPLE_ETH_SPI_MOSI_GPIO,
    .sclk_io_num = CONFIG_EXAMPLE_ETH_SPI_SCLK_GPIO,
    .quadwp_io_num = -1,
    .quadhd_io_num = -1,
ESP_ERROR_CHECK(spi_bus_initialize(CONFIG_EXAMPLE_ETH_SPI_HOST, &buscfg, 1));
// 配置 SPI 从机设备
spi_device_interface_config_t spi_devcfg = {
    .mode = 0,
    .clock_speed_hz = CONFIG_EXAMPLE_ETH_SPI_CLOCK_MHZ * 1000 * 1000,
    .spics_io_num = CONFIG_EXAMPLE_ETH_SPI_CS_GPIO,
    .queue_size = 20
/* dm9051 ethernet driver is based on spi driver */
eth_dm9051_config_t dm9051_config = ETH_DM9051_DEFAULT_CONFIG(CONFIG_EXAMPLE_ETH_SPI_HOST, &spi_devcfg);
dm9051_config.int_gpio_num = CONFIG_EXAMPLE_ETH_SPI_INT_GPIO;
esp_eth_mac_t *mac = esp_eth_mac_new_dm9051(&dm9051_config, &mac_config);
esp_eth_phy_t *phy = esp_eth_phy_new_dm9051(&phy_config);
当为 SPI-Ethernet 模块（例如 DM9051）创建 MAC 和 PHY 实例时，由于 PHY 是集成在模块中的，因此调用的实例创建函数的后缀须保持一致（例如 esp_eth_mac_new_dm9051 和 esp_eth_phy_new_dm9051 搭配使用）。
针对不同的以太网模块，或是为了满足特定 PCB 上的 SPI 时序，SPI 从机设备配置（即 spi_device_interface_config_t）可能略有不同。具体配置请查看模块规格以及 ESP-IDF 中的示例。
安装驱动程序
安装以太网驱动程序需要结合 MAC 和 PHY 实例，并在 esp_eth_config_t 中配置一些额外的高级选项（即不仅限于 MAC 或 PHY 的选项）：
esp_eth_config_t::mac：由 MAC 生成器创建的实例（例如 esp_eth_mac_new_esp32()）。
esp_eth_config_t::phy：由 PHY 生成器创建的实例（例如 esp_eth_phy_new_ip101()）。
esp_eth_config_t::check_link_period_ms：以太网驱动程序会启用操作系统定时器来定期检查链接状态。该字段用于设置间隔时间，单位为毫秒。
esp_eth_config_t::stack_input：在大多数的以太网物联网应用中，驱动器接收的以太网帧会被传递到上层（如 TCP/IP 栈）。经配置，该字段为负责处理传入帧的函数。可以在安装驱动程序后，通过函数 esp_eth_update_input_path() 更新该字段。该字段支持在运行过程中进行更新。
esp_eth_config_t::on_lowlevel_init_done 和 esp_eth_config_t::on_lowlevel_deinit_done：这两个字段用于指定钩子函数，当去初始化或初始化低级别硬件时，会调用钩子函数。
ESP-IDF 在宏 ETH_DEFAULT_CONFIG 中为安装驱动程序提供了一个默认配置。
esp_eth_config_t config = ETH_DEFAULT_CONFIG(mac, phy); // 应用默认驱动程序配置
esp_eth_handle_t eth_handle = NULL; // 驱动程序安装完毕后，将得到驱动程序的句柄
esp_eth_driver_install(&config, &eth_handle); // 安装驱动程序
以太网驱动程序包含事件驱动模型，该模型会向用户空间发送有用及重要的事件。安装以太网驱动程序之前，需要首先初始化事件循环。有关事件驱动编程的更多信息，请参考 事件循环库。
/** 以太网事件的事件处理程序 */
static void eth_event_handler(void *arg, esp_event_base_t event_base,
                              int32_t event_id, void *event_data)
    uint8_t mac_addr[6] = {0};
    /* 可从事件数据中获得以太网驱动句柄 */
    esp_eth_handle_t eth_handle = *(esp_eth_handle_t *)event_data;
    switch (event_id) {
    case ETHERNET_EVENT_CONNECTED:
        esp_eth_ioctl(eth_handle, ETH_CMD_G_MAC_ADDR, mac_addr);




    

        ESP_LOGI(TAG, "Ethernet Link Up");
        ESP_LOGI(TAG, "Ethernet HW Addr %02x:%02x:%02x:%02x:%02x:%02x",
                    mac_addr[0], mac_addr[1], mac_addr[2], mac_addr[3], mac_addr[4], mac_addr[5]);
        break;
    case ETHERNET_EVENT_DISCONNECTED:
        ESP_LOGI(TAG, "Ethernet Link Down");
        break;
    case ETHERNET_EVENT_START:
        ESP_LOGI(TAG, "Ethernet Started");
        break;
    case ETHERNET_EVENT_STOP:
        ESP_LOGI(TAG, "Ethernet Stopped");
        break;
    default:
        break;
esp_event_loop_create_default(); // 创建一个在后台运行的默认事件循环
esp_event_handler_register(ETH_EVENT, ESP_EVENT_ANY_ID, &eth_event_handler, NULL); // 注册以太网事件处理程序（用于在发生 link up/down 等事件时，处理特定的用户相关内容）
连接驱动程序至 TCP/IP 协议栈
现在，以太网驱动程序已经完成安装。但对应 OSI（开放式系统互连模型）来看，目前阶段仍然属于第二层（即数据链路层）。这意味着可以检测到 link up/down 事件，获得用户空间的 MAC 地址，但无法获得 IP 地址，当然也无法发送 HTTP 请求。ESP-IDF 中使用的 TCP/IP 协议栈是 LwIP，关于 LwIP 的更多信息，请参考 LwIP。
要将以太网驱动程序连接至 TCP/IP 协议栈，需要以下三步：
为以太网驱动程序创建网络接口
将网络接口连接到以太网驱动程序
注册 IP 事件处理程序
有关网络接口的更多信息，请参考 Network Interface。
/** IP_EVENT_ETH_GOT_IP 的事件处理程序 */
static void got_ip_event_handler(void *arg, esp_event_base_t event_base,
                                 int32_t event_id, void *event_data)
    ip_event_got_ip_t *event = (ip_event_got_ip_t *) event_data;
    const esp_netif_ip_info_t *ip_info = &event->ip_info;
    ESP_LOGI(TAG, "Ethernet Got IP Address");
    ESP_LOGI(TAG, "~~~~~~~~~~~");
    ESP_LOGI(TAG, "ETHIP:" IPSTR, IP2STR(&ip_info->ip));
    ESP_LOGI(TAG, "ETHMASK:" IPSTR, IP2STR(&ip_info->netmask));
    ESP_LOGI(TAG, "ETHGW:" IPSTR, IP2STR(&ip_info->gw));
    ESP_LOGI(TAG, "~~~~~~~~~~~");
esp_netif_init()); // 初始化 TCP/IP 网络接口（在应用程序中应仅调用一次）
esp_netif_config_t cfg = ESP_NETIF_DEFAULT_ETH(); // 应用以太网的默认网络接口配置
esp_netif_t *eth_netif = esp_netif_new(&cfg); // 为以太网驱动程序创建网络接口
esp_netif_attach(eth_netif, esp_eth_new_netif_glue(eth_handle)); // 将以太网驱动程序连接至 TCP/IP 协议栈
esp_event_handler_register(IP_EVENT, IP_EVENT_ETH_GOT_IP, &got_ip_event_handler, NULL); // 注册用户定义的 IP 事件处理程序
esp_eth_start(eth_handle); // 启动以太网驱动程序状态机
推荐在完成整个以太网驱动和网络接口的初始化后，再注册用户定义的以太网/IP 事件处理程序，也就是把注册事件处理程序作为启动以太网驱动程序的最后一步。这样可以确保以太网驱动程序或网络接口将首先执行以太网/IP 事件，从而保证在执行用户定义的处理程序时，系统处于预期状态。
以太网驱动程序的杂项控制
以下功能只支持在安装以太网驱动程序后调用。
关闭以太网驱动程序：esp_eth_stop()
更新以太网数据输入路径：esp_eth_update_input_path()
获取/设置以太网驱动程序杂项内容：esp_eth_ioctl()
/* 获取 MAC 地址 */
uint8_t mac_addr[6];
memset(mac_addr, 0, sizeof(mac_addr));
esp_eth_ioctl(eth_handle, ETH_CMD_G_MAC_ADDR, mac_addr);
ESP_LOGI(TAG, "Ethernet MAC Address: %02x:%02x:%02x:%02x:%02x:%02x",
         mac_addr[0], mac_addr[1], mac_addr[2], mac_addr[3], mac_addr[4], mac_addr[5]);
/* 获取 PHY 地址 */
int phy_addr = -1;
esp_eth_ioctl(eth_handle, ETH_CMD_G_PHY_ADDR, &phy_addr);
ESP_LOGI(TAG, "Ethernet PHY Address: %d", phy_addr);
数据流量控制
受 RAM 大小限制，在网络拥堵时，MCU 上的以太网通常仅能处理有限数量的帧。发送站的数据传输速度可能快于对等端的接收能力。以太网数据流量控制机制允许接收节点向发送方发出信号，要求暂停传输，直到接收方跟上。这项功能是通过暂停帧实现的，该帧定义在 IEEE 802.3x 中。
暂停帧是一种特殊的以太网帧，用于携带暂停命令，其 EtherType 字段为 0x8808，控制操作码为 0x0001。只有配置为全双工操作的节点组可以发送暂停帧。当节点组希望暂停链路的另一端时，它会发送一个暂停帧到 48 位的保留组播地址 01-80-C2-00-00-01。暂停帧中也包括请求暂停的时间段，以两字节的整数形式发送，值的范围从 0 到 65535。
安装以太网驱动程序后，数据流量控制功能默认禁用，可以通过以下方式启用此功能：
bool flow_ctrl_enable = true;
esp_eth_ioctl(eth_handle, ETH_CMD_S_FLOW_CTRL, &flow_ctrl_enable);
需注意，暂停帧是在自动协商期间由 PHY 向对等端公布的。只有当链路的两边都支持暂停帧时，以太网驱动程序才会发送暂停帧。
应用示例
以太网基本示例：ethernet/basic
以太网 iperf 示例：ethernet/iperf
以太网到 Wi-Fi AP“路由器”：network/eth2ap
Wi-Fi station 到以太网 “网桥”：network/sta2eth
大多数协议示例也适用于以太网：protocols
自定义 PHY 驱动程序
目前市面上已有多家 PHY 制造商提供了大量的芯片组合。ESP-IDF 现已支持数种 PHY 芯片，但是由于价格、功能、库存等原因，有时用户还是无法找到一款能满足其实际需求的芯片。
好在 IEEE 802.3 在其 22.2.4 管理功能部分对 EMAC 和 PHY 之间的管理接口进行了标准化。该部分定义了所谓的 ”MII 管理接口”规范，用于控制 PHY 和收集 PHY 的状态，还定义了一组管理寄存器来控制芯片行为、链接属性、自动协商配置等。在 ESP-IDF 中，这项基本的管理功能是由 esp_eth/src/esp_eth_phy_802_3.c 实现的，这也大大降低了创建新的自定义 PHY 芯片驱动的难度。
由于一些 PHY 芯片可能不符合 IEEE 802.3 第 22.2.4 节的规定，所以请首先查看 PHY 数据手册。不过，就算芯片不符合规定，依旧可以创建自定义 PHY 驱动程序，只是由于需要自行定义所有的 PHY 管理功能，这个过程将变得较为复杂。
ESP-IDF 以太网驱动程序所需的大部分 PHY 管理功能都已涵盖在 esp_eth/src/esp_eth_phy_802_3.c 中。不过对于以下几项，可能仍需针对不同芯片开发具体的管理功能：
链接状态。此项总是由使用的具体芯片决定
芯片初始化。即使不存在严格的限制，也应进行自定义，以确保使用的是符合预期的芯片
芯片的具体功能配置
创建自定义 PHY 驱动程序的步骤：
请根据 PHY 数据手册，定义针对供应商的特定注册表布局。示例请参见 esp_eth/src/esp_eth_phy_ip101.c。
准备衍生的 PHY 管理对象信息结构，该结构：
必须至少包含 IEEE 802.3 phy_802_3_t 父对象
可选包含支持非 IEEE 802.3 或自定义功能所需的额外变量。示例请参见 esp_eth/src/esp_eth_phy_ksz80xx.c。
定义针对芯片的特定管理回调功能。
初始化 IEEE 802.3 父对象并重新分配针对芯片的特定管理回调功能。
实现新的自定义 PHY 驱动程序后，你可以通过 ESP-IDF 组件管理中心 将驱动分享给其他用户。
API 参考
Header File
components/esp_eth/include/esp_eth.h
This header file can be included with:
#include "esp_eth.h"
This header file is a part of the API provided by the esp_eth component. To declare that your component depends on esp_eth




    
, add the following to your CMakeLists.txt:
REQUIRES esp_eth
PRIV_REQUIRES esp_eth
This header file is a part of the API provided by the esp_eth component. To declare that your component depends on esp_eth, add the following to your CMakeLists.txt:
REQUIRES esp_eth
PRIV_REQUIRES esp_eth
esp_err_t esp_eth_driver_install(const esp_eth_config_t *config, esp_eth_handle_t *out_hdl)

Install Ethernet driver. 
config -- [in] configuration of the Ethernet driver 
out_hdl -- [out] handle of Ethernet driver
ESP_OK: install esp_eth driver successfully
ESP_ERR_INVALID_ARG: install esp_eth driver failed because of some invalid argument
ESP_ERR_NO_MEM: install esp_eth driver failed because there's no memory for driver
ESP_FAIL: install esp_eth driver failed because some other error occurred 
esp_err_t esp_eth_driver_uninstall(esp_eth_handle_t hdl)

Uninstall Ethernet driver. 
It's not recommended to uninstall Ethernet driver unless it won't get used any more in application code. To uninstall Ethernet driver, you have to make sure, all references to the driver are released. Ethernet driver can only be uninstalled successfully when reference counter equals to one.
hdl -- [in] handle of Ethernet driver
ESP_OK: uninstall esp_eth driver successfully
ESP_ERR_INVALID_ARG: uninstall esp_eth driver failed because of some invalid argument
ESP_ERR_INVALID_STATE: uninstall esp_eth driver failed because it has more than one reference
ESP_FAIL: uninstall esp_eth driver failed because some other error occurred 
esp_err_t esp_eth_start(esp_eth_handle_t hdl)

Start Ethernet driver ONLY in standalone mode (i.e. without TCP/IP stack) 
This API will start driver state machine and internal software timer (for checking link status).
hdl -- [in] handle of Ethernet driver
ESP_OK: start esp_eth driver successfully
ESP_ERR_INVALID_ARG: start esp_eth driver failed because of some invalid argument
ESP_ERR_INVALID_STATE: start esp_eth driver failed because driver has started already
ESP_FAIL: start esp_eth driver failed because some other error occurred 
ESP_OK: stop esp_eth driver successfully
ESP_ERR_INVALID_ARG: stop esp_eth driver failed because of some invalid argument
ESP_ERR_INVALID_STATE: stop esp_eth driver failed because driver has not started yet
ESP_FAIL: stop esp_eth driver failed because some other error occurred 
esp_err_t esp_eth_update_input_path(esp_eth_handle_t hdl, esp_err_t (*stack_input)(esp_eth_handle_t hdl, uint8_t *buffer, uint32_t length, void *priv), void *priv)

Update Ethernet data input path (i.e. specify where to pass the input buffer) 
After install driver, Ethernet still don't know where to deliver the input buffer. In fact, this API registers a callback function which get invoked when Ethernet received new packets.
hdl -- [in] handle of Ethernet driver 
stack_input -- [in] function pointer, which does the actual process on incoming packets 
priv -- [in] private resource, which gets passed to stack_input callback without any modification 
ESP_OK: update input path successfully
ESP_ERR_INVALID_ARG: update input path failed because of some invalid argument
ESP_FAIL: update input path failed because some other error occurred 
esp_err_t esp_eth_transmit(esp_eth_handle_t hdl, void *buf, size_t length)

General Transmit. 
hdl -- [in] handle of Ethernet driver 
buf -- [in] buffer of the packet to transfer 
length -- [in] length of the buffer to transfer
ESP_OK: transmit frame buffer successfully
ESP_ERR_INVALID_ARG: transmit frame buffer failed because of some invalid argument
ESP_ERR_INVALID_STATE: invalid driver state (e.i. driver is not started)
ESP_ERR_TIMEOUT: transmit frame buffer failed because HW was not get available in predefined period
ESP_FAIL: transmit frame buffer failed because some other error occurred 
esp_err_t esp_eth_transmit_vargs(esp_eth_handle_t hdl, uint32_t argc, ...)

Special Transmit with variable number of arguments. 
hdl -- [in] handle of Ethernet driver 
argc -- [in] number variable arguments 
... -- variable arguments 
ESP_OK: transmit successfull
ESP_ERR_INVALID_STATE: invalid driver state (e.i. driver is not started)
ESP_ERR_TIMEOUT: transmit frame buffer failed because HW was not get available in predefined period
ESP_FAIL: transmit frame buffer failed because some other error occurred 
esp_err_t esp_eth_ioctl(esp_eth_handle_t hdl, esp_eth_io_cmd_t cmd, void *data)

Misc IO function of Etherent driver. 
The following common IO control commands are supported: 

ETH_CMD_S_MAC_ADDR sets Ethernet interface MAC address. data argument is pointer to MAC address buffer with expected size of 6 bytes. 
ETH_CMD_G_MAC_ADDR gets Ethernet interface MAC address. data argument is pointer to a buffer to which MAC address is to be copied. The buffer size must be at least 6 bytes. 
ETH_CMD_S_PHY_ADDR sets PHY address in range of <0-31>. data argument is pointer to memory of uint32_t datatype from where the configuration option is read. 
ETH_CMD_G_PHY_ADDR gets PHY address. data argument is pointer to memory of uint32_t datatype to which the PHY address is to be stored. 
ETH_CMD_S_AUTONEGO enables or disables Ethernet link speed and duplex mode autonegotiation. data argument is pointer to memory of bool datatype from which the configuration option is read. Preconditions: Ethernet driver needs to be stopped. 
ETH_CMD_G_AUTONEGO gets current configuration of the Ethernet link speed and duplex mode autonegotiation. data argument is pointer to memory of bool datatype to which the current configuration is to be stored. 
ETH_CMD_S_SPEED sets the Ethernet link speed. data argument is pointer to memory of eth_speed_t datatype from which the configuration option is read. Preconditions: Ethernet driver needs to be stopped and auto-negotiation disabled. 
ETH_CMD_G_SPEED gets current Ethernet link speed. data argument is pointer to memory of eth_speed_t datatype to which the speed is to be stored. 
ETH_CMD_S_PROMISCUOUS sets/resets Ethernet interface promiscuous mode. data




    
 argument is pointer to memory of bool datatype from which the configuration option is read. 
ETH_CMD_S_FLOW_CTRL sets/resets Ethernet interface flow control. data argument is pointer to memory of bool datatype from which the configuration option is read. 
ETH_CMD_S_DUPLEX_MODE sets the Ethernet duplex mode. data argument is pointer to memory of eth_duplex_t datatype from which the configuration option is read. Preconditions: Ethernet driver needs to be stopped and auto-negotiation disabled. 
ETH_CMD_G_DUPLEX_MODE gets current Ethernet link duplex mode. data argument is pointer to memory of eth_duplex_t datatype to which the duplex mode is to be stored. 
ETH_CMD_S_PHY_LOOPBACK sets/resets PHY to/from loopback mode. data argument is pointer to memory of bool datatype from which the configuration option is read.
Note that additional control commands may be available for specific MAC or PHY chips. Please consult specific MAC or PHY documentation or driver code. 
hdl -- [in] handle of Ethernet driver 
cmd -- [in] IO control command 
data -- [inout] address of data for set command or address where to store the data when used with get command
ESP_OK: process io command successfully
ESP_ERR_INVALID_ARG: process io command failed because of some invalid argument
ESP_FAIL: process io command failed because some other error occurred
ESP_ERR_NOT_SUPPORTED: requested feature is not supported
esp_err_t esp_eth_increase_reference(esp_eth_handle_t hdl)

Increase Ethernet driver reference. 
Ethernet driver handle can be obtained by os timer, netif, etc. It's dangerous when thread A is using Ethernet but thread B uninstall the driver. Using reference counter can prevent such risk, but care should be taken, when you obtain Ethernet driver, this API must be invoked so that the driver won't be uninstalled during your using time.
hdl -- [in] handle of Ethernet driver 
ESP_OK: increase reference successfully
ESP_ERR_INVALID_ARG: increase reference failed because of some invalid argument 
esp_err_t esp_eth_decrease_reference(esp_eth_handle_t hdl)

Decrease Ethernet driver reference. 
hdl -- [in] handle of Ethernet driver 
ESP_OK: increase reference successfully
ESP_ERR_INVALID_ARG: increase reference failed because of some invalid argument 
esp_err_t (*stack_input)(esp_eth_handle_t eth_handle, uint8_t *buffer, uint32_t length, void *priv)

Input frame buffer to user's stack. 
Param eth_handle
[in] handle of Ethernet driver 
Param buffer
[in] frame buffer that will get input to upper stack 
Param length
[in] length of the frame buffer
Return
ESP_OK: input frame buffer to upper stack successfully
ESP_FAIL: error occurred when inputting buffer to upper stack 
esp_err_t (*on_lowlevel_init_done)(esp_eth_handle_t eth_handle)

Callback function invoked when lowlevel initialization is finished. 
Param eth_handle
[in] handle of Ethernet driver
Return
ESP_OK: process extra lowlevel initialization successfully
ESP_FAIL: error occurred when processing extra lowlevel initialization 
esp_err_t (*on_lowlevel_deinit_done)(esp_eth_handle_t eth_handle)

Callback function invoked when lowlevel deinitialization is finished. 
Param eth_handle
[in] handle of Ethernet driver
Return
ESP_OK: process extra lowlevel deinitialization successfully
ESP_FAIL: error occurred when processing extra lowlevel deinitialization 
esp_err_t (*read_phy_reg)(esp_eth_handle_t eth_handle, uint32_t phy_addr, uint32_t phy_reg, uint32_t *reg_value)

Read PHY register. 
Usually the PHY register read/write function is provided by MAC (SMI interface), but if the PHY device is managed by other interface (e.g. I2C), then user needs to implement the corresponding read/write. Setting this to NULL means your PHY device is managed by MAC's SMI interface.
Param eth_handle
[in] handle of Ethernet driver 
Param phy_addr
[in] PHY chip address (0~31) 
Param phy_reg
[in] PHY register index code 
Param reg_value
[out] PHY register value
Return
ESP_OK: read PHY register successfully
ESP_ERR_INVALID_ARG: read PHY register failed because of invalid argument
ESP_ERR_TIMEOUT: read PHY register failed because of timeout
ESP_FAIL: read PHY register failed because some other error occurred 
esp_err_t (*write_phy_reg)(esp_eth_handle_t eth_handle, uint32_t phy_addr, uint32_t phy_reg, uint32_t reg_value)

Write PHY register. 
Usually the PHY register read/write function is provided by MAC (SMI interface), but if the PHY device is managed by other interface (e.g. I2C), then user needs to implement the corresponding read/write. Setting this to NULL means your PHY device is managed by MAC's SMI interface.
Param eth_handle
[in] handle of Ethernet driver 
Param phy_addr
[in] PHY chip address (0~31) 
Param phy_reg
[in] PHY register index code 
Param reg_value
[in] PHY register value
Return
ESP_OK: write PHY register successfully
ESP_ERR_INVALID_ARG: read PHY register failed because of invalid argument
ESP_ERR_TIMEOUT: write PHY register failed because of timeout
ESP_FAIL: write PHY register failed because some other error occurred 
struct esp_eth_phy_reg_rw_data_t

Data structure to Read/Write PHY register via ioctl API. 
Public Members
uint32_t reg_addr

PHY register address 
This header file is a part of the API provided by the esp_eth component. To declare that your component depends on esp_eth, add the following to your CMakeLists.txt:
REQUIRES esp_eth
PRIV_REQUIRES esp_eth
esp_err_t (*phy_reg_read




    
)(esp_eth_mediator_t *eth, uint32_t phy_addr, uint32_t phy_reg, uint32_t *reg_value)

Read PHY register. 
Param eth
[in] mediator of Ethernet driver 
Param phy_addr
[in] PHY Chip address (0~31) 
Param phy_reg
[in] PHY register index code 
Param reg_value
[out] PHY register value
Return
ESP_OK: read PHY register successfully
ESP_FAIL: read PHY register failed because some error occurred 
esp_err_t (*phy_reg_write)(esp_eth_mediator_t *eth, uint32_t phy_addr, uint32_t phy_reg, uint32_t reg_value)

Write PHY register. 
Param eth
[in] mediator of Ethernet driver 
Param phy_addr
[in] PHY Chip address (0~31) 
Param phy_reg
[in] PHY register index code 
Param reg_value
[in] PHY register value
Return
ESP_OK: write PHY register successfully
ESP_FAIL: write PHY register failed because some error occurred 
esp_err_t (*stack_input)(esp_eth_mediator_t *eth, uint8_t *buffer, uint32_t length)

Deliver packet to upper stack. 
Param eth
[in] mediator of Ethernet driver 
Param buffer
[in] packet buffer 
Param length
[in] length of the packet
Return
ESP_OK: deliver packet to upper stack successfully
ESP_FAIL: deliver packet failed because some error occurred 
esp_err_t (*on_state_changed)(esp_eth_mediator_t *eth, esp_eth_state_t state, void *args)

Callback on Ethernet state changed. 
Param eth
[in] mediator of Ethernet driver 
Param state
[in] new state 
Param args
[in] optional argument for the new state
Return
ESP_OK: process the new state successfully
ESP_FAIL: process the new state failed because some error occurred 
This header file is a part of the API provided by the esp_eth component. To declare that your component depends on esp_eth, add the following to your CMakeLists.txt:
REQUIRES esp_eth
PRIV_REQUIRES esp_eth
esp_eth_mac_t *esp_eth_mac_new_esp32(const eth_esp32_emac_config_t *esp32_config, const eth_mac_config_t *config)

Create ESP32 Ethernet MAC instance. 
esp32_config -- EMAC specific configuration 
config -- Ethernet MAC configuration
instance: create MAC instance successfully
NULL: create MAC instance failed because some error occurred 
esp_err_t (*set_mediator)(esp_eth_mac_t *mac, esp_eth_mediator_t *eth)

Set mediator for Ethernet MAC. 
Param mac
[in] Ethernet MAC instance 
Param eth
[in] Ethernet mediator
Return
ESP_OK: set mediator for Ethernet MAC successfully
ESP_ERR_INVALID_ARG: set mediator for Ethernet MAC failed because of invalid argument 
ESP_OK: initialize Ethernet MAC successfully
ESP_ERR_TIMEOUT: initialize Ethernet MAC failed because of timeout
ESP_FAIL: initialize Ethernet MAC failed because some other error occurred 
esp_err_t (*transmit)(esp_eth_mac_t *mac, uint8_t *buf, uint32_t length)

Transmit packet from Ethernet MAC. 
Returned error codes may differ for each specific MAC chip. 
Param mac
[in] Ethernet MAC instance 
Param buf
[in] packet buffer to transmit 
Param length
[in] length of packet
Return
ESP_OK: transmit packet successfully
ESP_ERR_INVALID_SIZE: number of actually sent bytes differs to expected
ESP_FAIL: transmit packet failed because some other error occurred
esp_err_t (*transmit_vargs)(esp_eth_mac_t *mac, uint32_t argc, va_list args)

Transmit packet from Ethernet MAC constructed with special parameters at Layer2. 
Typical intended use case is to make possible to construct a frame from multiple higher layer buffers without a need of buffer reallocations. However, other use cases are not limited.
Returned error codes may differ for each specific MAC chip. 
Param mac
[in] Ethernet MAC instance 
Param argc
[in] number variable arguments 
Param args
[in] variable arguments
Return
ESP_OK: transmit packet successfully
ESP_ERR_INVALID_SIZE: number of actually sent bytes differs to expected
ESP_FAIL: transmit packet failed because some other error occurred
esp_err_t (*receive)(esp_eth_mac_t




    
 *mac, uint8_t *buf, uint32_t *length)

Receive packet from Ethernet MAC. 
Memory of buf is allocated in the Layer2, make sure it get free after process. 
Before this function got invoked, the value of "length" should set by user, equals the size of buffer. After the function returned, the value of "length" means the real length of received data.
Param mac
[in] Ethernet MAC instance 
Param buf
[out] packet buffer which will preserve the received frame 
Param length
[out] length of the received packet
Return
ESP_OK: receive packet successfully
ESP_ERR_INVALID_ARG: receive packet failed because of invalid argument
ESP_ERR_INVALID_SIZE: input buffer size is not enough to hold the incoming data. in this case, value of returned "length" indicates the real size of incoming data.
ESP_FAIL: receive packet failed because some other error occurred 
esp_err_t (*read_phy_reg)(esp_eth_mac_t *mac, uint32_t phy_addr, uint32_t phy_reg, uint32_t *reg_value)

Read PHY register. 
Param mac
[in] Ethernet MAC instance 
Param phy_addr
[in] PHY chip address (0~31) 
Param phy_reg
[in] PHY register index code 
Param reg_value
[out] PHY register value
Return
ESP_OK: read PHY register successfully
ESP_ERR_INVALID_ARG: read PHY register failed because of invalid argument
ESP_ERR_INVALID_STATE: read PHY register failed because of wrong state of MAC
ESP_ERR_TIMEOUT: read PHY register failed because of timeout
ESP_FAIL: read PHY register failed because some other error occurred 
esp_err_t (*write_phy_reg)(esp_eth_mac_t *mac, uint32_t phy_addr, uint32_t phy_reg, uint32_t reg_value)

Write PHY register. 
Param mac
[in] Ethernet MAC instance 
Param phy_addr
[in] PHY chip address (0~31) 
Param phy_reg
[in] PHY register index code 
Param reg_value
[in] PHY register value
Return
ESP_OK: write PHY register successfully
ESP_ERR_INVALID_STATE: write PHY register failed because of wrong state of MAC
ESP_ERR_TIMEOUT: write PHY register failed because of timeout
ESP_FAIL: write PHY register failed because some other error occurred 
ESP_OK: set MAC address successfully
ESP_ERR_INVALID_ARG: set MAC address failed because of invalid argument
ESP_FAIL: set MAC address failed because some other error occurred 
ESP_OK: get MAC address successfully
ESP_ERR_INVALID_ARG: get MAC address failed because of invalid argument
ESP_FAIL: get MAC address failed because some other error occurred 
esp_err_t (*set_speed)(esp_eth_mac_t *mac, eth_speed_t speed)

Set speed of MAC. 
Param ma:c
[in] Ethernet MAC instance 
Param speed
[in] MAC speed
Return
ESP_OK: set MAC speed successfully
ESP_ERR_INVALID_ARG: set MAC speed failed because of invalid argument
ESP_FAIL: set MAC speed failed because some other error occurred 
esp_err_t (*set_duplex)(esp_eth_mac_t *mac, eth_duplex_t duplex)

Set duplex mode of MAC. 
Param mac
[in] Ethernet MAC instance 
Param duplex
[in] MAC duplex
Return
ESP_OK: set MAC duplex mode successfully
ESP_ERR_INVALID_ARG: set MAC duplex failed because of invalid argument
ESP_FAIL: set MAC duplex failed because some other error occurred 
esp_err_t (*set_link)(esp_eth_mac_t *mac, eth_link_t link)

Set link status of MAC. 
Param mac
[in] Ethernet MAC instance 
Param link
[in] Link status
Return
ESP_OK: set link status successfully
ESP_ERR_INVALID_ARG: set link status failed because of invalid argument
ESP_FAIL: set link status failed because some other error occurred 
esp_err_t (*set_promiscuous)(esp_eth_mac_t *mac, bool enable)

Set promiscuous of MAC. 
Param mac
[in] Ethernet MAC instance 
Param enable
[in] set true to enable promiscuous mode; set false to disable promiscuous mode
Return
ESP_OK: set promiscuous mode successfully
ESP_FAIL: set promiscuous mode failed because some error occurred 
esp_err_t (*enable_flow_ctrl)(esp_eth_mac_t *mac, bool enable)

Enable flow control on MAC layer or not. 
Param mac
[in] Ethernet MAC instance 
Param enable
[in] set true to enable flow control; set false to disable flow control
Return
ESP_OK: set flow control successfully
ESP_FAIL: set flow control failed because some error occurred 
esp_err_t (*set_peer_pause_ability)(esp_eth_mac_t *mac, uint32_t ability)

Set the PAUSE ability of peer node. 
Param mac
[in] Ethernet MAC instance 
Param ability
[in] zero indicates that pause function is supported by link partner; non-zero indicates that pause function is not supported by link partner
Return
ESP_OK: set peer pause ability successfully
ESP_FAIL: set peer pause ability failed because some error occurred 
esp_err_t




    
 (*custom_ioctl)(esp_eth_mac_t *mac, uint32_t cmd, void *data)

Custom IO function of MAC driver. This function is intended to extend common options of esp_eth_ioctl to cover specifics of MAC chip. 
This function may not be assigned when the MAC chip supports only most common set of configuration options.
Param mac
[in] Ethernet MAC instance 
Param cmd
[in] IO control command 
Param data
[inout] address of data for set command or address where to store the data when used with get command
Return
ESP_OK: process io command successfully
ESP_ERR_INVALID_ARG: process io command failed because of some invalid argument
ESP_FAIL: process io command failed because some other error occurred
ESP_ERR_NOT_SUPPORTED: requested feature is not supported 
struct eth_spi_custom_driver_config_t

Custom SPI Driver Configuration. This structure declares configuration and callback functions to access Ethernet SPI module via user's custom SPI driver. 
Public Members
void *config

Custom driver specific configuration data used by init() function. 
Type and its content is fully under user's control 
Return
spi_ctx: when initialization is successful, a pointer to context structure holding all variables needed for subsequent SPI access operations (e.g. SPI bus identification, mutexes, etc.)
NULL: driver initialization failed
esp_err_t (*read)(void *spi_ctx, uint32_t cmd, uint32_t addr, void *data, uint32_t data_len)

Custom driver SPI read. 
The read function is responsible to construct command, address and data fields of the SPI frame in format expected by particular SPI Ethernet module
Param spi_ctx
[in] a pointer to driver specific context structure 
Param cmd
[in] command 
Param addr
[in] register address 
Param data
[out] read data 
Param data_len
[in] read data length in bytes
Return
ESP_OK: read was successful
ESP_FAIL: read failed
any other failure codes are allowed to be used to provide failure isolation 
esp_err_t (*write)(void *spi_ctx, uint32_t cmd, uint32_t addr, const void *data, uint32_t data_len)

Custom driver SPI write. 
The write function is responsible to construct command, address and data fields of the SPI frame in format expected by particular SPI Ethernet module
Param spi_ctx
[in] a pointer to driver specific context structure 
Param cmd
[in] command 
Param addr
[in] register address 
Param data
[in] data to write 
Param data_len
[in] length of data to write in bytes
Return
ESP_OK: write was successful
ESP_FAIL: write failed
any other failure codes are allowed to be used to provide failure isolation 
enumerator EMAC_CLK_EXT_IN

Input RMII Clock from external. EMAC Clock GPIO number needs to be configured when this option is selected. 
MAC will get RMII clock from outside. Note that ESP32 only supports GPIO0 to input the RMII clock. 
enumerator EMAC_APPL_CLK_OUT_GPIO

Output RMII Clock from internal APLL Clock available at GPIO0. 
GPIO0 can be set to output a pre-divided PLL clock (test only!). Enabling this option will configure GPIO0 to output a 50MHz clock. In fact this clock doesn’t have directly relationship with EMAC peripheral. Sometimes this clock won’t work well with your PHY chip. You might need to add some extra devices after GPIO0 (e.g. inverter). Note that outputting RMII clock on GPIO0 is an experimental practice. If you want the Ethernet to work with WiFi, don’t select GPIO0 output mode for stability. 
This header file is a part of the API provided by the esp_eth component. To declare that your component depends on esp_eth, add the following to your CMakeLists.txt:
REQUIRES esp_eth
PRIV_REQUIRES esp_eth
esp_eth_phy_t *esp_eth_phy_new_ip101(const eth_phy_config_t *config)

Create a PHY instance of IP101. 
config -- [in] configuration of PHY
instance: create PHY instance successfully
NULL: create PHY instance failed because some error occurred 
esp_eth_phy_t *esp_eth_phy_new_rtl8201(const eth_phy_config_t *config)

Create a PHY instance of RTL8201. 
config -- [in] configuration of PHY
instance: create PHY instance successfully
NULL: create PHY instance failed because some error occurred 
esp_eth_phy_t *esp_eth_phy_new_lan87xx(const eth_phy_config_t *config)

Create a PHY instance of LAN87xx. 
config -- [in] configuration of PHY
instance: create PHY instance successfully
NULL: create PHY instance failed because some error occurred 
esp_eth_phy_t *esp_eth_phy_new_dp83848(const eth_phy_config_t *config)

Create a PHY instance of DP83848. 
config -- [in] configuration of PHY
instance: create PHY instance successfully
NULL: create PHY instance failed because some error occurred 
esp_eth_phy_t




    
 *esp_eth_phy_new_ksz80xx(const eth_phy_config_t *config)

Create a PHY instance of KSZ80xx. 
The phy model from the KSZ80xx series is detected automatically. If the driver is unable to detect a supported model, NULL is returned.
Currently, the following models are supported: KSZ8001, KSZ8021, KSZ8031, KSZ8041, KSZ8051, KSZ8061, KSZ8081, KSZ8091
config -- [in] configuration of PHY
instance: create PHY instance successfully
NULL: create PHY instance failed because some error occurred 
esp_err_t (*set_mediator)(esp_eth_phy_t *phy, esp_eth_mediator_t *mediator)

Set mediator for PHY. 
Param phy
[in] Ethernet PHY instance 
Param mediator
[in] mediator of Ethernet driver
Return
ESP_OK: set mediator for Ethernet PHY instance successfully
ESP_ERR_INVALID_ARG: set mediator for Ethernet PHY instance failed because of some invalid arguments 
esp_err_t (*autonego_ctrl)(esp_eth_phy_t *phy, eth_phy_autoneg_cmd_t cmd, bool *autonego_en_stat)

Configure auto negotiation. 
Param phy
[in] Ethernet PHY instance 
Param cmd
[in] Configuration command, it is possible to Enable (restart), Disable or get current status of PHY auto negotiation 
Param autonego_en_stat
[out] Address where to store current status of auto negotiation configuration
Return
ESP_OK: restart auto negotiation successfully
ESP_FAIL: restart auto negotiation failed because some error occurred
ESP_ERR_INVALID_ARG: invalid command 
esp_err_t (*set_link)(esp_eth_phy_t *phy, eth_link_t link)

Set Ethernet PHY link status. 
Param phy
[in] Ethernet PHY instance 
Param link
[in] new link status
Return
ESP_OK: set Ethernet PHY link status successfully
ESP_FAIL: set Ethernet PHY link status failed because some error occurred 
esp_err_t (*pwrctl)(esp_eth_phy_t *phy, bool enable)

Power control of Ethernet PHY. 
Param phy
[in] Ethernet PHY instance 
Param enable
[in] set true to power on Ethernet PHY; ser false to power off Ethernet PHY
Return
ESP_OK: control Ethernet PHY power successfully
ESP_FAIL: control Ethernet PHY power failed because some error occurred 
esp_err_t (*set_addr)(esp_eth_phy_t *phy, uint32_t addr)

Set PHY chip address. 
Param phy
[in] Ethernet PHY instance 
Param addr
[in] PHY chip address
Return
ESP_OK: set Ethernet PHY address successfully
ESP_FAIL: set Ethernet PHY address failed because some error occurred 
esp_err_t (*get_addr)(esp_eth_phy_t *phy, uint32_t *addr)

Get PHY chip address. 
Param phy
[in] Ethernet PHY instance 
Param addr
[out] PHY chip address
Return
ESP_OK: get Ethernet PHY address successfully
ESP_ERR_INVALID_ARG: get Ethernet PHY address failed because of invalid argument 
esp_err_t (*advertise_pause_ability)(esp_eth_phy_t *phy, uint32_t ability)

Advertise pause function supported by MAC layer. 
Param phy
[in] Ethernet PHY instance 
Param addr
[out] Pause ability
Return
ESP_OK: Advertise pause ability successfully
ESP_ERR_INVALID_ARG: Advertise pause ability failed because of invalid argument 
esp_err_t (*loopback)(esp_eth_phy_t *phy, bool enable)

Sets the PHY to loopback mode. 
Param phy
[in] Ethernet PHY instance 
Param enable
[in] enables or disables PHY loopback
Return
ESP_OK: PHY instance loopback mode has been configured successfully
ESP_FAIL: PHY instance loopback configuration failed because some error occurred 
esp_err_t (*set_speed)(esp_eth_phy_t *phy, eth_speed_t speed)

Sets PHY speed mode. 
Autonegotiation feature needs to be disabled prior to calling this function for the new setting to be applied
Param phy
[in] Ethernet PHY instance 
Param speed
[in] Speed mode to be set
Return
ESP_OK: PHY instance speed mode has been configured successfully
ESP_FAIL: PHY instance speed mode configuration failed because some error occurred 
esp_err_t (*set_duplex)(




    
esp_eth_phy_t *phy, eth_duplex_t duplex)

Sets PHY duplex mode. 
Autonegotiation feature needs to be disabled prior to calling this function for the new setting to be applied
Param phy
[in] Ethernet PHY instance 
Param duplex
[in] Duplex mode to be set
Return
ESP_OK: PHY instance duplex mode has been configured successfully
ESP_FAIL: PHY instance duplex mode configuration failed because some error occurred 
esp_err_t (*custom_ioctl)(esp_eth_phy_t *phy, uint32_t cmd, void *data)

Custom IO function of PHY driver. This function is intended to extend common options of esp_eth_ioctl to cover specifics of PHY chip. 
This function may not be assigned when the PHY chip supports only most common set of configuration options.
Param phy
[in] Ethernet PHY instance 
Param cmd
[in] IO control command 
Param data
[inout] address of data for set command or address where to store the data when used with get command
Return
ESP_OK: process io command successfully
ESP_ERR_INVALID_ARG: process io command failed because of some invalid argument
ESP_FAIL: process io command failed because some other error occurred
ESP_ERR_NOT_SUPPORTED: requested feature is not supported 
This header file is a part of the API provided by the esp_eth component. To declare that your component depends on esp_eth, add the following to your CMakeLists.txt:
REQUIRES esp_eth
PRIV_REQUIRES esp_eth
esp_err_t esp_eth_phy_802_3_set_mediator(phy_802_3_t *phy_802_3, esp_eth_mediator_t *eth)

Set Ethernet mediator. 
phy_802_3 -- IEEE 802.3 PHY object infostructure 
eth -- Ethernet mediator pointer 
ESP_OK: Ethermet mediator set successfuly
ESP_ERR_INVALID_ARG: if eth is NULL
esp_err_t esp_eth_phy_802_3_autonego_ctrl(phy_802_3_t *phy_802_3, eth_phy_autoneg_cmd_t cmd, bool *autonego_en_stat)

Control autonegotiation mode of Ethernet PHY. 
phy_802_3 -- IEEE 802.3 PHY object infostructure 
cmd -- autonegotiation command enumeration 
autonego_en_stat -- [out] autonegotiation enabled flag 
ESP_OK: Ethernet PHY autonegotiation configured successfuly
ESP_FAIL: Ethernet PHY autonegotiation configuration fail because some error occured
ESP_ERR_INVALID_ARG: invalid value of cmd
esp_err_t esp_eth_phy_802_3_pwrctl(phy_802_3_t *phy_802_3, bool enable)

Power control of Ethernet PHY. 
phy_802_3 -- IEEE 802.3 PHY object infostructure 
enable -- set true to power ON Ethernet PHY; set false to power OFF Ethernet PHY 
ESP_OK: Ethernet PHY power down mode set successfuly
ESP_FAIL: Ethernet PHY power up or power down failed because some error occured 
esp_err_t esp_eth_phy_802_3_set_addr(phy_802_3_t *phy_802_3, uint32_t addr)

Set Ethernet PHY address. 
phy_802_3 -- IEEE 802.3 PHY object infostructure 
addr -- new PHY address 
ESP_OK: Ethernet PHY address set 
esp_err_t esp_eth_phy_802_3_get_addr(phy_802_3_t *phy_802_3, uint32_t *addr)

Get Ethernet PHY address. 
phy_802_3 -- IEEE 802.3 PHY object infostructure 
addr -- [out] Ethernet PHY address 
ESP_OK: Ethernet PHY address read successfuly
ESP_ERR_INVALID_ARG: addr pointer is NULL
esp_err_t esp_eth_phy_802_3_advertise_pause_ability(phy_802_3_t *phy_802_3, uint32_t ability)

Advertise pause function ability. 
phy_802_3 -- IEEE 802.3 PHY object infostructure 
ability -- enable or disable pause ability 
ESP_OK: pause ability set successfuly
ESP_FAIL: Advertise pause function ability failed because some error occured 
esp_err_t esp_eth_phy_802_3_loopback(phy_802_3_t *phy_802_3, bool enable)

Set Ethernet PHY loopback mode. 
phy_802_3 -- IEEE 802.3 PHY object infostructure 
enable -- set true to enable loopback; set false to disable loopback 
ESP_OK: Ethernet PHY loopback mode set successfuly
ESP_FAIL: Ethernet PHY loopback configuration failed because some error occured 
esp_err_t esp_eth_phy_802_3_set_speed(phy_802_3_t *phy_802_3, eth_speed_t speed)

Set Ethernet PHY speed. 
phy_802_3 -- IEEE 802.3 PHY object infostructure 
speed -- new speed of Ethernet PHY link 
ESP_OK: Ethernet PHY speed set successfuly
ESP_FAIL: Set Ethernet PHY speed failed because some error occured 
esp_err_t esp_eth_phy_802_3_set_duplex(phy_802_3_t




    
 *phy_802_3, eth_duplex_t duplex)

Set Ethernet PHY duplex mode. 
phy_802_3 -- IEEE 802.3 PHY object infostructure 
duplex -- new duplex mode for Ethernet PHY link 
ESP_OK: Ethernet PHY duplex mode set successfuly
ESP_ERR_INVALID_STATE: unable to set duplex mode to Half if loopback is enabled
ESP_FAIL: Set Ethernet PHY duplex mode failed because some error occured 
esp_err_t esp_eth_phy_802_3_set_link(phy_802_3_t *phy_802_3, eth_link_t link)

Set Ethernet PHY link status. 
phy_802_3 -- IEEE 802.3 PHY object infostructure 
link -- new link status 
ESP_OK: Ethernet PHY link set successfuly 
esp_err_t esp_eth_phy_802_3_del(phy_802_3_t *phy_802_3)

Delete Ethernet PHY infostructure. 
phy_802_3 -- IEEE 802.3 PHY object infostructure 
ESP_OK: Ethrnet PHY infostructure deleted 
esp_err_t esp_eth_phy_802_3_reset_hw(phy_802_3_t *phy_802_3, uint32_t reset_assert_us)

Performs hardware reset with specific reset pin assertion time. 
phy_802_3 -- IEEE 802.3 PHY object infostructure 
reset_assert_us -- Hardware reset pin assertion time 
ESP_OK: reset Ethernet PHY successfully 
esp_err_t esp_eth_phy_802_3_detect_phy_addr(esp_eth_mediator_t *eth, int *detected_addr)

Detect PHY address. 
eth -- Mediator of Ethernet driver 
detected_addr -- [out] a valid address after detection 
ESP_OK: detect phy address successfully
ESP_ERR_INVALID_ARG: invalid parameter
ESP_ERR_NOT_FOUND: can't detect any PHY device
ESP_FAIL: detect phy address failed because some error occurred 
esp_err_t esp_eth_phy_802_3_basic_phy_init(phy_802_3_t *phy_802_3)

Performs basic PHY chip initialization. 
It should be called as the first function in PHY specific driver instance
phy_802_3 -- IEEE 802.3 PHY object infostructure 
ESP_OK: initialized Ethernet PHY successfully
ESP_FAIL: initialization of Ethernet PHY failed because some error occurred
ESP_ERR_INVALID_ARG: invalid argument
ESP_ERR_NOT_FOUND: PHY device not detected
ESP_ERR_TIMEOUT: MII Management read/write operation timeout
ESP_ERR_INVALID_STATE: PHY is in invalid state to perform requested operation 
esp_err_t esp_eth_phy_802_3_basic_phy_deinit(phy_802_3_t *phy_802_3)

Performs basic PHY chip de-initialization. 
It should be called as the last function in PHY specific driver instance
phy_802_3 -- IEEE 802.3 PHY object infostructure 
ESP_OK: de-initialized Ethernet PHY successfully
ESP_FAIL: de-initialization of Ethernet PHY failed because some error occurred
ESP_ERR_TIMEOUT: MII Management read/write operation timeout
ESP_ERR_INVALID_STATE: PHY is in invalid state to perform requested operation 
esp_err_t esp_eth_phy_802_3_read_oui(phy_802_3_t *phy_802_3, uint32_t *oui)

Reads raw content of OUI field. 
phy_802_3 -- IEEE 802.3 PHY object infostructure 
oui -- [out] OUI value 
ESP_OK: OUI field read successfully
ESP_FAIL: OUI field read failed because some error occurred
ESP_ERR_INVALID_ARG: invalid oui argument
ESP_ERR_TIMEOUT: MII Management read/write operation timeout
ESP_ERR_INVALID_STATE: PHY is in invalid state to perform requested operation 
esp_err_t esp_eth_phy_802_3_read_manufac_info(phy_802_3_t *phy_802_3, uint8_t *model, uint8_t *rev)

Reads manufacturer’s model and revision number. 
phy_802_3 -- IEEE 802.3 PHY object infostructure 
model -- [out] Manufacturer’s model number (can be NULL when not required) 
rev -- [out] Manufacturer’s revision number (can be NULL when not required) 
ESP_OK: Manufacturer’s info read successfully
ESP_FAIL: Manufacturer’s info read failed because some error occurred
ESP_ERR_TIMEOUT: MII Management read/write operation timeout
ESP_ERR_INVALID_STATE: PHY is in invalid state to perform requested operation 
esp_err_t esp_eth_phy_802_3_get_mmd_addr(phy_802_3_t *phy_802_3, uint8_t devaddr, uint16_t *mmd_addr)

Reads MDIO device's internal address register. 
phy_802_3 -- IEEE 802.3 PHY object infostructure 
devaddr -- Address of MDIO device 
mmd_addr -- [out] Current address stored in device's register 
ESP_OK: Address register read successfuly
ESP_FAIL: Address register read failed because of some error occured
ESP_ERR_INVALID_ARG: Device address provided is out of range (hardware limits device address to 5 bits) 
esp_err_t esp_eth_phy_802_3_set_mmd_addr(phy_802_3_t *phy_802_3, uint8_t devaddr, uint16_t mmd_addr)

Write to DIO device's internal address register. 
phy_802_3 -- IEEE 802.3 PHY object infostructure 
devaddr -- Address of MDIO device 
mmd_addr -- [out] New value of MDIO device's address register value 
ESP_OK: Address register written to successfuly
ESP_FAIL: Address register write failed because of some error occured
ESP_ERR_INVALID_ARG: Device address provided is out of range (hardware limits device address to 5 bits) 
esp_err_t esp_eth_phy_802_3_read_mmd_data(phy_802_3_t *phy_802_3, uint8_t devaddr, esp_eth_phy_802_3_mmd_func_t function, uint32_t *data)

Read data of MDIO device's memory at address register. 
phy_802_3 -- IEEE 802.3 PHY object infostructure 
devaddr -- Address of MDIO device 
function -- MMD function 
data -- [out] Data read from the device's memory 
ESP_OK: Memory read successfuly
ESP_FAIL: Memory read failed because of some error occured
ESP_ERR_INVALID_ARG: Device address provided is out of range (hardware limits device address to 5 bits) or MMD access function is invalid 
esp_err_t esp_eth_phy_802_3_write_mmd_data(phy_802_3_t *phy_802_3, uint8_t devaddr, esp_eth_phy_802_3_mmd_func_t function, uint32_t data)

Write data to MDIO device's memory at address register. 
phy_802_3 -- IEEE 802.3 PHY object infostructure 
devaddr -- Address of MDIO device 
function -- MMD function 
data -- [out] Data to write to the device's memory 
ESP_OK: Memory written successfuly
ESP_FAIL: Memory write failed because of some error occured
ESP_ERR_INVALID_ARG: Device address provided is out of range (hardware limits device address to 5 bits) or MMD access function is invalid 
esp_err_t esp_eth_phy_802_3_read_mmd_register(phy_802_3_t *phy_802_3, uint8_t devaddr, uint16_t mmd_addr, uint32_t *data)

Set MMD address to mmd_addr with function MMD_FUNC_NOINCR and read contents to *data. 
phy_802_3 -- IEEE 802.3 PHY object infostructure 
devaddr -- Address of MDIO device 
mmd_addr -- Address of MDIO device register 
data -- [out] Data read from the device's memory 
ESP_OK: Memory read successfuly
ESP_FAIL: Memory read failed because of some error occured
ESP_ERR_INVALID_ARG: Device address provided is out of range (hardware limits device address to 5 bits) 
esp_err_t esp_eth_phy_802_3_write_mmd_register(phy_802_3_t *phy_802_3, uint8_t devaddr, uint16_t mmd_addr, uint32_t data)

Set MMD address to mmd_addr with function MMD_FUNC_NOINCR and write data. 
phy_802_3 -- IEEE 802.3 PHY object infostructure 
devaddr -- Address of MDIO device 
mmd_addr -- Address of MDIO device register 
data -- [out] Data to write to the device's memory 
ESP_OK: Memory written to successfuly
ESP_FAIL: Memory write failed because of some error occured
ESP_ERR_INVALID_ARG: Device address provided is out of range (hardware limits device address to 5 bits) 
inline phy_802_3_t *esp_eth_phy_into_phy_802_3(esp_eth_phy_t *phy)

Returns address to parent IEEE 802.3 PHY object infostructure. 
phy -- Ethernet PHY instance 
phy_802_3_t*

address to parent IEEE 802.3 PHY object infostructure 
esp_err_t esp_eth_phy_802_3_obj_config_init(phy_802_3_t *phy_802_3, const eth_phy_config_t *config)

Initializes configuration of parent IEEE 802.3 PHY object infostructure. 
phy_802_3 -- Address to IEEE 802.3 PHY object infostructure 
config -- Configuration of the IEEE 802.3 PHY object 
ESP_OK: configuration initialized successfully
ESP_ERR_INVALID_ARG: invalid config argument 
This header file is a part of the API provided by the esp_eth component. To declare that your component depends on esp_eth, add the following to your CMakeLists.txt:
REQUIRES esp_eth
PRIV_REQUIRES esp_eth