--- title: "W6300 Zephyr Driver PR #102727: Under Review" url: "https://maker.wiznet.io/Grace_Koo/projects/boards-add-support-wiznet-w6300-evb-pico2/" markdown_url: "https://maker.wiznet.io/Grace_Koo/projects/boards-add-support-wiznet-w6300-evb-pico2/md" type: "UCC: User Created Content" author: "Ethan-cho" author_url: "https://github.com/zephyrproject-rtos/zephyr/pull/102727" editor: "WIZnet" editor_url: "https://maker.wiznet.io/" original_author: "Ethan-cho" original_url: "https://github.com/zephyrproject-rtos/zephyr/pull/102727" published: "2026-04-15" language: "en" likes: 0 views: 278 comments: 0 source: "WIZnet Makers (https://maker.wiznet.io/)" --- # W6300 Zephyr Driver PR #102727: Under Review > A Zephyr RTOS driver PR for WIZnet W6300 on RP2350, using bit-bang SPI + MACRAW mode. Currently under review. Original author: Ethan-cho (source: https://github.com/zephyrproject-rtos/zephyr/pull/102727) ## Article ## What This PR Does **This is an Ethernet driver PR that enables WIZnet W6300 support on Zephyr RTOS.** It brings the W6300-EVB-Pico2 board (RP2350 + W6300) into the Zephyr ecosystem — adding the driver code, Devicetree binding, board definition files, and documentation all in one go. | Item | Details | | --- | --- | | **Core Chip** | WIZnet W6300 (Hardwired TCP/IP, 10/100 Ethernet) | | **MCU** | Raspberry Pi RP2350 (W6300-EVB-Pico2) | | **OS / Firmware** | Zephyr RTOS | | **Interface** | Bit-bang SPI / 500kHz (MACRAW mode) | | **PR Status** | Open / Under review (as of Jan 2026) | Authored by WIZnet engineer Ethan-cho (Manjae Cho), the PR is currently going through community review with the goal of merging into the Zephyr mainline repository. --- ## Background: W6300 on Zephyr Zephyr RTOS is an open-source real-time operating system used across a wide range of domains — industrial IoT, wearables, automotive embedded systems, and more. Managed by the Linux Foundation with over 14,000 GitHub stars, getting a driver merged here means the chip becomes immediately usable across countless Zephyr-based projects. The W6300 is WIZnet's latest Ethernet controller, supporting up to 90Mbps throughput via a hardwired TCP/IP stack and QSPI interface. Until now, no official Zephyr driver existed for the W6300. This PR is the first attempt to fill that gap. --- ## The Role of WIZnet W6300 In this driver, the W6300 handles **Ethernet MAC/PHY and packet I/O**. It operates in MACRAW mode, passing raw Ethernet frames directly to the host (RP2350), with TCP/IP processing handled by the Zephyr network stack. ### ⚠️ What's Not Implemented Yet Two of the W6300's headline features are **not yet implemented** in this PR. | Feature | W6300 Support | This PR | | --- | --- | --- | | **QSPI (4-wire high-speed)** | ✅ Up to 150MHz, 90Mbps+ | ❌ Not implemented — bit-bang SPI at 500kHz | | **Hardware TCP/IP Stack (TOE)** | ✅ 8 hardware sockets | ❌ Not implemented — MACRAW + Zephyr stack | In short, this is a **baseline implementation that drives the W6300 via bit-bang SPI (500kHz) in MACRAW mode**. The chip's performance advantages — QSPI throughput and TOE offloading — are not utilized at this stage. The approach follows Zephyr's established driver patterns: MACRAW is the standard integration method for Ethernet controllers in Zephyr, and the existing W5500 driver uses the same approach. --- ## How It Works **Bit-bang SPI Layer** The W6300 and RP2350 communicate via the `zephyr,spi-bitbang` driver, which software-toggles GPIO17 (CLK), GPIO18 (MOSI), GPIO19 (MISO), and GPIO16 (CS) directly. The maximum clock is set to 500kHz. The driver uses W6300's binary register protocol — selecting a register block via BSB (Block Select Bit), then exchanging a 16-bit address and data. ```c // W6300 SPI frame structure (from driver code) uint8_t header[3] = { w6300_spi_instr(W6300_SPI_RWB_READ, bsb), (uint8_t)(addr >> 8), (uint8_t)addr, }; ``` **MACRAW RX Loop** A dedicated Zephyr thread (`eth_w6300`) polls the W6300's receive buffer on interrupt, then passes Ethernet frames up to the Zephyr network stack via `net_recv_data`. **Devicetree Configuration** All hardware configuration — pin assignments, SPI bus, interrupt, and MAC address — is declared in Devicetree. The `zephyr,random-mac-address` property enables dynamic MAC address assignment. ```plaintext /* W6300-EVB-Pico2 Devicetree (actual) */ spi_w6300: spi-bitbang { compatible = "zephyr,spi-bitbang"; clk-gpios = <&gpio0 17 GPIO_ACTIVE_HIGH>; mosi-gpios = <&gpio0 18 GPIO_ACTIVE_HIGH>; miso-gpios = <&gpio0 19 GPIO_ACTIVE_HIGH>; cs-gpios = <&gpio0 16 GPIO_ACTIVE_LOW>; ethernet: w6300@0 { compatible = "wiznet,w6300"; spi-max-frequency = <500000>; int-gpios = <&gpio0 15 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>; reset-gpios = <&gpio0 22 GPIO_ACTIVE_LOW>; zephyr,random-mac-address; }; }; ``` **Zephyr Network Stack Integration** By implementing Zephyr's `ethernet.h` API, the driver abstracts the W6300 entirely from the application layer. Any network feature Zephyr supports — DHCP, TCP/UDP, IPv4/IPv6 — works out of the box. --- ## Hardware Overview | Component | Details | | --- | --- | | **Ethernet Controller** | WIZnet W6300 | | **MCU** | Raspberry Pi RP2350 | | **Board** | W6300-EVB-Pico2 | | **Interface** | Bit-bang SPI, 500kHz (GPIO15–22) | | **Flash** | 2MB (external, per dtsi) | | **Form Factor** | Raspberry Pi Pico2-compatible pinout | --- ## What This Driver Opens Up Once merged into the Zephyr mainline, the W6300 becomes an immediately usable component across any Zephyr-based platform or application. | Use Case | Why It Fits | | --- | --- | | **Industrial IoT / Edge Computing** | Zephyr supports industrial certifications such as IEC 61508. A merged W6300 driver provides a ready reference for industrial Ethernet node designs. | | **Smart Building / Automation** | Combining W6300 Ethernet with Zephyr's Matter, Modbus, and MQTT stacks simplifies gateway development. | | **Medical / Defense Embedded** | Provides a stable, RTOS-based Ethernet controller reference for environments requiring certified software stacks. | | **ODM/OEM** | Gives product teams a solid basis for adopting W6300 as a standard component in Zephyr-based designs. Porting to MCUs beyond RP2350 is relatively straightforward given the driver structure. | The current lack of QSPI support also means there is room for the driver to grow — the W6300's hardware is capable of far more than what this initial implementation uses. --- ## Tech Stack Summary | Component | Details | | --- | --- | | **Ethernet Controller** | WIZnet W6300 (Hardwired TCP/IP, SPI/QSPI, 10/100Mbps) | | **MCU / Board** | Raspberry Pi RP2350 / W6300-EVB-Pico2 | | **OS** | Zephyr RTOS (Linux Foundation) | | **Driver Mode** | Bit-bang SPI 500kHz + MACRAW (Zephyr ethernet API) | | **Configuration** | Devicetree + Kconfig | | **QSPI Support** | Not implemented (bit-bang SPI at 500kHz) | | **TOE (Hardware TCP/IP)** | Not implemented (Zephyr network stack used) | | **License** | Apache 2.0 (Zephyr standard) | | **PR** | zephyrproject-rtos/zephyr #102727 | --- ## Closing This PR is the first step toward W6300 becoming an officially supported part in the Zephyr RTOS ecosystem. The current implementation is minimal — bit-bang SPI at 500kHz with MACRAW — but establishing W6300 within Zephyr's driver framework is itself significant. Once a WIZnet chip is registered as an officially supported component in one of the world's largest embedded RTOS projects, industrial and commercial adoption naturally follows. --- > **Project Link** > > - Zephyr PR: --- Source: https://maker.wiznet.io/Grace_Koo/projects/boards-add-support-wiznet-w6300-evb-pico2/