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Lists key features like processing capability, wireless rate, supported standards, interfaces, and OS.
Shows front and back views of the HLK-7628D module.
Illustrates the module's internal architecture and key components.
Depicts the module's peripheral interface connections and common usage scenarios.
Details module type, chip, kernel, frequency, storage, flash, temperature, humidity, and dimensions.
Lists supported interfaces like WiFi, Ethernet, UART, SPI, I2C, I2S, PWM, and GPIO.
Specifies input voltage, no-load operating current, and supply current requirement.
Provides detailed RF parameters for 802.11b, 802.11g, and 802.11n standards.
Visual representation of module pins and their labels.
Details pin names, types, functions, and default features for serial passthrough firmware.
Provides detailed mechanical dimensions of the module in millimeters.
Outlines the recommended temperature profile for reflow soldering to prevent damage.
Compares module chip functions with GPIO assignments for OpenWrt.
The HLK-7628D module from Hi-Link is a low-cost, low-power IoT module designed for a wide range of smart device and cloud service applications. Based on MediaTek's MT7628DN chip, this module offers robust data processing capabilities and a rich set of interfaces, making it suitable for custom development and second-development projects.
The HLK-7628D module serves as a central component for IoT applications, providing both wireless and wired networking capabilities. At its core, it features a powerful MCU operating at up to 580MHz, enabling efficient data processing for various tasks. The module supports the 802.11b/g/n wireless standard, offering a 150M wireless rate and supporting both 20MHz and 40MHz channel bandwidths. This allows for flexible deployment in different wireless environments. It can operate in AP (Access Point), STA (Station), and mixed AP/STA modes, providing versatility for network configurations.
For wired connectivity, the HLK-7628D integrates five 10/100M adaptive network ports, facilitating connections to multiple Ethernet devices. This makes it ideal for applications requiring a local network hub or gateway functionality.
The module is equipped with a comprehensive array of peripheral interfaces to support diverse functionalities. These include multiple UART (3-way), SPI (1-way), I2C (1-way), I2S (1-way), PWM (1-way), and GPIO (above 8-way) interfaces. These interfaces allow the module to communicate with a wide variety of sensors, actuators, and other external components, enabling complex IoT solutions. Additionally, it features a USB2.0 host interface, expanding its capabilities for connecting external USB devices. The module also supports SDXC and eMMC interfaces, providing options for external storage.
The HLK-7628D is designed to run on Linux and OpenWrt operating systems, offering a flexible and open development environment. The factory default firmware, based on Linux, provides transparent transmission functions for Ethernet, WiFi, UARTO, and UART1, simplifying initial setup for basic communication tasks. Developers have the option to rewrite the firmware with OpenWrt or the original MTK Linux program to tailor the module's behavior to specific application requirements.
The HLK-7628D is engineered for ease of integration and flexible deployment in IoT ecosystems. Its compact dimensions (18mm × 32.8mm × 2.8mm) make it suitable for space-constrained designs. The module operates within a broad ambient temperature range of -40°C to 85°C and can function in humidity levels from 10% to 95% (non-condensing), ensuring reliability in various environmental conditions.
The module's power supply requirements are straightforward, needing a DC 3.3±0.2V input. With a no-load operating current of 170±50mA and a supply current requirement of ≥800mA, it is designed for efficient power consumption, which is crucial for battery-powered or energy-sensitive IoT devices.
The default pin functions are optimized for common IoT applications. For instance, the WDT_RST_N pin offers multi-functional control: a 1-second pull-down activates the WeChat AirKiss function, a 3-second pull-down exits transparent transmission and enters AT mode, and a 6-second pull-down restores the module to default settings. This provides convenient methods for configuration and recovery.
The module supports multiple encryption methods, including WEP64/128, TKIP, AES, WPA, WPA2, and WAPI, ensuring secure wireless communication. It also incorporates QoS, WMM, and WMM-PS features to manage network traffic effectively, prioritizing critical data for improved performance in demanding applications.
The built-in powerful PMU (Power Management Unit) contributes to the module's overall power efficiency and stability. The support for 16 multiple BSSIDs allows for the creation of multiple virtual access points, enhancing network management and segmentation capabilities.
For antenna connectivity, the module includes an on-board antenna RF interface. If an external antenna is preferred, the default external antenna pin can be connected by removing the antenna base and replacing it with a 0 ohm resistor, offering flexibility in antenna design.
Maintenance of the HLK-7628D module primarily involves adhering to proper handling procedures during assembly and, if necessary, firmware updates. The module is designed for reflow soldering, and strict adherence to the specified temperature curve is critical to prevent damage. The manual provides a detailed reflow soldering temperature curve, emphasizing that significant deviations can harm the module.
The module's design includes a thermal pad in the middle, which should be grounded during installation to ensure proper heat dissipation and long-term reliability. The symmetrical pin layout simplifies board design and assembly.
For development and debugging, the module offers various interfaces like JTAG, which can be utilized for in-depth analysis and troubleshooting. The availability of Linux and OpenWrt SDKs facilitates ongoing software maintenance and upgrades, allowing developers to implement patches, add new features, or adapt to evolving security requirements.
The remarks on the pin definition highlight important considerations for external connections. For instance, pins related to the chip's start-up cannot be pulled down or connected to a drive source externally, which is crucial information for preventing damage during circuit design. The blue-colored entries in the remarks column indicate functions supported by the factory's default firmware, guiding developers on out-of-the-box capabilities.
Regular firmware updates, especially for security patches and performance enhancements, are a key aspect of maintaining the module's functionality and security in deployed systems. The open nature of the Linux and OpenWrt platforms supports a community-driven approach to maintenance, with readily available resources and updates.
General| Model | HLK-7628D |
|---|---|
| Category | Control Unit |
| Chipset | MT7628DAN |
| CPU Architecture | MIPS 24KEc |
| CPU Frequency | 580 MHz |
| RAM | 64 MB |
| Flash Memory | 16 MB |
| Wi-Fi Standards | 802.11b/g/n |
| Wi-Fi Frequency | 2.4 GHz |
| Input Voltage | 5V |
| USB Ports | 1 |
| Operating Temperature | -20°C to 70°C |
| Efficiency | 85% |
| Protection | Over-voltage, Over-current |
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