| Parameter / Model | E77-900MBL-01 (Test Board) | E77-900M22S (Onboard Module) |
|---|---|---|
| Main IC / Platform | STM32WL55 Dual-Core MCU (LoRa) | STM32WL55 (System-on-Chip) |
| Operating Frequency Band | 868 MHz / 915 MHz (850 - 925 MHz) | 868 MHz / 915 MHz (850 - 925 MHz) |
| Transmit Power (Max) | 22 dBm | 22 dBm (approx. 160 mW) |
| Receiving Sensitivity | -148 dBm @ LoRa | -148 dBm @ LoRa |
| Host Interface / Communication | Micro-USB / USB-to-UART (CP2102) | UART, SPI, I2C, GPIO |
| Operating Voltage | 5V USB Power / 3.3V Pin Header | 1.8V - 3.6V DC |
| Antenna Interface | SMA-K (Female Outer Screw, Inner Hole) | IPEX / Stamp Hole Pad |
| Modulation Technology | LoRa, (G)FSK, (G)MSK, BPSK | LoRa, (G)FSK, (G)MSK, BPSK |
Practical Application Scenarios
1. Urban Smart Metering Infrastructure and AMR Field Testing
In automated meter reading (AMR) projects for water, gas, and electricity grids, engineers utilize the E77-900MBL-01 test kit to conduct real-world link budget evaluations across dense urban environments. Paired with Ebyte industrial Modbus DTUs (such as E810 series) and remote telemetry terminals, the E77-900M22S integrated on this kit enables rapid verification of LoRa/LoRaWAN coverage, checking data packet delivery ratios under sub-GHz signal penetration through walls and subterranean meter vaults.
2. Distributed Environmental Monitoring in Precision Agriculture
For agricultural IoT deployments, the board connects seamlessly to environmental sensor arrays (soil moisture, temperature, pH sensors) using its broken-out GPIO pin headers. The onboard 22dBm transmit power and high -148dBm receiving sensitivity allow engineers to stream sensor payload data to field concentrators over distances up to 5 km in open space. Developers can prototype low-power sleep modes and battery-drenches direct on the USB evaluation setup before mass-producing custom PCB nodes.
3. Industrial Automation and PLC Remote IO Expansion
In smart factory automation, control engineers combine the E77-900MBL-01 with industrial PLCs or Raspberry Pi single-board computers via the serial interface to replace costly RS485 wiring runs. By bypassing or configuring the onboard STM32WL55 firmware via jumpers, the kit serves as a wireless bridge transmitting Modbus RTU telemetry between distributed IO expansion modules (e.g., Ebyte ME31 series) and central SCADA systems without packet loss in noisy electromagnetic environments.
FAQ Section
1. How does the E77-900MBL-01 evaluation board handle power isolation between USB 5V and module 3.3V supply?
The E77-900MBL-01 integrates an onboard high-efficiency LDO regulator to convert the 5V USB bus voltage into a clean, regulated 3.3V DC rail required by the integrated STM32WL55-based E77-900M22S module. The power circuit features dedicated decoupling capacitor networks to filter out high-frequency switching noise originating from the host USB interface, preserving maximum RF receiving sensitivity (-148dBm) during desktop prototyping and spectrum analysis.
2. Can the onboard USB-to-UART circuit be disconnected to allow external microcontrollers to communicate directly with the E77-900M22S module?
Yes, the MBL series test board incorporates onboard jumper pin headers along the data routes. By removing the default jumper caps, developers can isolate the onboard USB-to-UART bridge (CP2102) and hook up external host microcontrollers (such as STM32, Arduino, ESP32, or industrial gateways) directly to the UART, SPI, or SWD programming pins for custom firmware flashing and system integration.
3. What programming interfaces and development frameworks are supported for the onboard STM32WL55 SoC?
Because the E77-900M22S module is built upon the dual-core STM32WL55 microcontroller (Cortex-M4 and Cortex-M0+), developers can program the test board via the standard SWD interface using tools like STM32CubeIDE, Keil MDK, or IAR Embedded Workbench. The board natively supports STM32CubeWL expansion packages, enabling full implementation of LoRaWAN 1.0.3/1.0.4 protocol stacks and proprietary sub-GHz P2P networks.
