README.md

Dummy PHY (EMAC to EMAC)

The Dummy PHY component enables you a direct EMAC to EMAC communication between two Ethernet capable devices without usage of external PHY transceiver. The design idea is to provide EMAC to EMAC connection between two devices without any modification to ESP-IDF Ethernet driver.

Note that usage of the Dummy PHY component does not conform with the RevMII standard! As such, it does not provide any management interface and so the speed/duplex mode needs to be statically configured to the same mode in both devices. Default configuration is 100Mbps/full duplex mode. If you need to change it, use esp_eth_ioctl() function with ETH_CMD_S_SPEED or ETH_CMD_S_DUPLEX_MODE command.

API

Steps to use the component in an example code

1. Add this component to your project using idf.py add-dependency command.
2. Include esp_eth_phy_dummy.h
3. Create a dummy phy driver instance by calling esp_eth_phy_new_dummyand initialize Ethernet as you are used to. The only difference is to set SMI GPIOs to -1 since the management interface is not utilized.

   // Init common MAC and PHY configs to default
   eth_mac_config_t mac_config = ETH_MAC_DEFAULT_CONFIG();
   eth_phy_config_t phy_config = ETH_PHY_DEFAULT_CONFIG();
   
   // Update PHY config based on board specific configuration
   phy_config.reset_gpio_num = -1; // no HW reset
   
   // Init vendor specific MAC config to default
   eth_esp32_emac_config_t esp32_emac_config = ETH_ESP32_EMAC_DEFAULT_CONFIG();
   // Update vendor specific MAC config based on board configuration
   // No SMI, speed/duplex must be statically configured the same in both devices
   // MIIM interface is not used since does not provide access to all registers

#if ESP_IDF_VERSION >= ESP_IDF_VERSION_VAL(5, 3, 0) esp32_emac_config.smi_gpio.mdc_num = -1; esp32_emac_config.smi_gpio.mdio_num = -1; #else esp32_emac_config.smi_mdc_gpio_num = -1; esp32_emac_config.smi_mdio_gpio_num = -1; #endif

// Create new ESP32 Ethernet MAC instance
esp_eth_mac_t *mac = esp_eth_mac_new_esp32(&esp32_emac_config, &mac_config);
// Create dummy PHY instance
esp_eth_phy_t *phy = esp_eth_phy_new_dummy(&phy_config);
```

Examples

Please refer to Simple Example for more information.