--- title: "esp-eth-drivers PR: W6100 Ethernet Driver Support Coming to ESP-IDF" url: "https://maker.wiznet.io/Grace_Koo/projects/feat-add-w6100-ethernet-driver-support-idfgh-17051/" markdown_url: "https://maker.wiznet.io/Grace_Koo/projects/feat-add-w6100-ethernet-driver-support-idfgh-17051/md" type: "UCC: User Created Content" author: "docwilco" author_url: "https://github.com/espressif/esp-eth-drivers/pull/133" editor: "WIZnet" editor_url: "https://maker.wiznet.io/" original_author: "docwilco" original_url: "https://github.com/espressif/esp-eth-drivers/pull/133" published: "2026-03-20" language: "en" tags: ["ESP32"] hardware: ["WIZnet W6100-EVB-Pico"] likes: 0 views: 875 comments: 0 source: "WIZnet Makers (https://maker.wiznet.io/)" --- # esp-eth-drivers PR: W6100 Ethernet Driver Support Coming to ESP-IDF > Community-contributed PR adds WIZnet W6100 Ethernet driver to ESP-IDF, enabling IPv4/IPv6 dual-stack communication over SPI on ESP32. Original author: docwilco (source: https://github.com/espressif/esp-eth-drivers/pull/133) ## Components - **WIZnet W6100-EVB-Pico** x 1 ([docs](https://www.wiznet.io/product-item/w6100-evb-pico/)) ## Documents and links - [GitHub PR: esp-eth-drivers #133](https://github.com/espressif/esp-eth-drivers/pull/133) (code) ## Article ## Open Source Contribution: ESP32 + W6100 Driver PR Under Review at Espressif ![](https://maker.wiznet.io/upload/ckeditor5/578275017%5F1774003988%2Epng) *https://github.com/espressif/esp-eth-drivers/pull/133* The ESP32 series is widely used for its built-in Wi-Fi and Bluetooth, but in industrial environments or applications requiring wired network connectivity, Ethernet is often essential. Espressif's official SDK, ESP-IDF, first introduced SPI Ethernet support in v4.4, including an official W5500 driver. While the W5500 driver has remained part of ESP-IDF through v5.x, its successor — the W6100, which adds native IPv6 support — has had no official driver available. In January 2026, developer `docwilco` submitted a Pull Request to Espressif's external Ethernet driver repository, [esp-eth-drivers](https://github.com/espressif/esp-eth-drivers), adding full W6100 driver support. This is the first publicly available implementation enabling the W6100 to work directly within the ESP-IDF ecosystem. --- ## The Role of the WIZnet W6100 ![](https://docs.wiznet.io/img/products/wiz610io/pinmap.png) *https://docs.wiznet.io/Product/ioModule/WIZ610io* The W6100 is a Hardwired TCP/IP Ethernet controller with the entire TCP/IP stack implemented in hardware. The MCU only needs to access socket registers over SPI to handle TCP, UDP, IPv4, and IPv6 communication — no software TCP/IP stack required. This makes it well-suited for resource-constrained MCU environments where reliable network performance is needed. Key differences from the W5500: | Feature | W5500 | W6100 | | --- | --- | --- | | IP Version | IPv4 only | IPv4 + IPv6 dual-stack | | Sockets | 8 | 8 | | Multicast Filtering | IPv4 block only | IPv4 and IPv6 independent control | | Max SPI Clock | 80 MHz | 80 MHz | | Speed | 10/100 Mbps | 10/100 Mbps | According to the contributor's own testing, the W6100 showed slightly higher throughput than the W5500 under identical conditions. --- ## How It Works The driver follows ESP-IDF's Ethernet driver architecture, separating the MAC and PHY layers. Here's a breakdown of the key design decisions. --- ### 1. wiznet_common — Shared 3-Layer Architecture Common code shared between W5500 and W6100 has been extracted into a `wiznet_common` component, covering the SPI transport (`wiznet_spi.c`), MAC common logic (`wiznet_mac_common.c`), and PHY common logic (`wiznet_phy_common.c`). The W6100 driver only needs to implement a `wiznet_chip_ops_t` structure defining chip-specific behavior; TX/RX handling, the EMAC task, and initialization sequences are all handled by the shared layer. The W5500 driver has been refactored to use the same structure. ```plaintext esp-eth-drivers/ ├── wiznet_common/ ← Shared layer for W5500 / W6100 │ ├── wiznet_spi.c SPI transport │ ├── wiznet_mac_common.c MAC TX/RX, EMAC task │ └── wiznet_phy_common.c PHY link detection, speed/duplex negotiation ├── w5500/ ← Depends on wiznet_common, chip-specific ops only └── w6100/ ← Depends on wiznet_common, chip-specific ops only ``` --- ### 2. WIZnet-Specific SPI Frame Format WIZnet chips use a non-standard SPI frame layout. The driver maps this to ESP-IDF's SPI driver fields as follows: ```plaintext [ command_bits = 16 ] [ address_bits = 8 ] [ data ] Address phase Control phase R/W data ``` For register reads of 4 bytes or less, the `SPI_TRANS_USE_RXDATA` flag is used to prevent 4-byte boundary overwrites. --- ### 3. Chip Initialization Sequence ```plaintext Software reset (clear RST bit in SYCR0) ↓ Wait for stabilization (60.3ms per datasheet) ↓ Poll W6100_REG_CIDR → verify Chip ID = 0x6100 ↓ Unlock NETLCKR → clear NETMR (disable IPv4/IPv6 blocking) ↓ Call wiznet_setup_default() (buffer allocation, socket mode, interrupt setup) ↓ Set SYCR1 IEN bit → enable global interrupt ``` --- ### 4. PHY Register Bit Interpretation — Inverted from W5500 The W6100's PHYSR (PHY Status Register) has **inverted** speed and duplex bit meanings compared to the W5500: | Bit | W5500 | W6100 | | --- | --- | --- | | speed = 1 | 100 Mbps | **10 Mbps** | | speed = 0 | 10 Mbps | **100 Mbps** | | duplex = 1 | Full | **Half** | | duplex = 0 | Half | **Full** | The driver abstracts this difference via the `speed_when_bit_set/clear` fields in `phy_wiznet_config_t` and an opmode lookup table, so upper layers remain chip-agnostic. --- ### 5. Multicast Filtering The W6100 controls multicast reception via the MMB (IPv4 multicast block) and MMB6 (IPv6 multicast block) bits in the Socket Mode Register (SMR). ```plaintext add_mac_filter(addr) called ↓ Identify by MAC address prefix: 01:00:5e:xx → IPv4 multicast 33:33:xx → IPv6 multicast ↓ Increment internal counter (v4_cnt / v6_cnt) counter 0 → 1: clear MMB / MMB6 bit (allow reception) rm_mac_filter(addr) called → decrement counter counter 1 → 0: re-enable MMB / MMB6 bit (block reception) ``` > While W5500 can only block IPv4 multicast, W6100 supports independent control of both IPv4 and IPv6 multicast. --- ### 6. ESP-IDF Version-Gated Features ```c // Multicast filter API only available on ESP-IDF v5.5 and above #if ESP_IDF_VERSION >= ESP_IDF_VERSION_VAL(5, 5, 0) mac->add_mac_filter = emac_w6100_add_mac_filter; mac->rm_mac_filter = emac_w6100_rm_mac_filter; mac->set_all_multicast = emac_w6100_set_all_multicast; #endif ``` | ESP-IDF Version | W5500 | W6100 | | --- | --- | --- | | v5.3 ~ v5.4 | Built-in driver | Basic Ethernet only | | v5.5 and above | External component | Full features incl. multicast filter | | v6.0 and above | External component | Full features | --- ## Potential Applications Once merged into esp-eth-drivers, the ESP32 + W6100 combination will be easily integrated into any project via the ESP-IDF Component Manager. Applicable scenarios include: - **Industrial automation and edge gateways**: Devices that require stable wired Ethernet rather than Wi-Fi, such as PLC-connected units or data acquisition gateways - **IPv6 transition environments**: New systems such as telecom infrastructure or smart home hubs that require native IPv6 support - **Multicast-dependent protocols**: Implementing mDNS, CoAP, or IGMP-based services on ESP32, where W6100's IPv6 multicast filtering becomes a practical advantage - **ODM/OEM design**: Migrating from W5500-based boards to W6100 is straightforward thanks to the shared `wiznet_common` layer, minimizing driver migration effort The contributor has also mentioned plans to develop a W6300 driver once this PR is merged, meaning the `wiznet_common` architecture is already positioned as the foundation for future WIZnet chip support. --- ## Technical Summary | Item | Details | | --- | --- | | WIZnet Chip | W6100 (backward compatible with W5500) | | MCU | ESP32-S3 (applicable across ESP32 family) | | Interface | SPI | | Framework | ESP-IDF v5.3 and above (including v6.0) | | Shared Component | wiznet_common | | Protocol Support | IPv4, IPv6, TCP, UDP, Multicast | | Speed | 10/100 Mbps, auto-negotiation / fixed mode | | Status | Open PR, under Espressif internal review | | Reference | [GitHub PR #133](https://github.com/espressif/esp-eth-drivers/pull/133) | --- ## Current Status This PR is currently under active development, with code feedback being exchanged between the contributor and Espressif's internal reviewers. Developers interested in the ESP32 + W6100 combination are encouraged to follow the PR. If you have thoughts on the implementation or test results, leaving a comment on the PR would be a helpful contribution. 👉 --- Source: https://maker.wiznet.io/Grace_Koo/projects/feat-add-w6100-ethernet-driver-support-idfgh-17051/