Version V1.2

This is the official release v1.2 of the eBoard_M66, featuring important hardware improvements and new functionality based on feedback and testing from v1.0 and v1.1.

➕ What’s New:

• Added two user-available LEDs for flexible status indication or custom functionality

Note

This version is recommended for all new development moving forward.

Version V1.1 - Hardware Revision Release

This is the second official release of the eBoard_M66, featuring important hardware improvements and new functionality based on feedback and testing from v1.0.

✅ What’s Fixed:

• JP1 jumper removed to eliminate the risk of microcontroller damage
• Voltage regulator EN pin now permanently tied to VIN for safe and stable operation
• Regulator control via MCU pin has been eliminated

➕ What’s New:

• Added two physical push buttons for user-defined input or control
• GSM_PWR signal is now routed to A0

Note

This version resolves all critical issues from v1.0 and is recommended for all new development moving forward.

Initial Release – Version 1.0

This is the first official release of the eBoard_M66, a shield-style development board designed for easy integration of the Quectel M66 GSM/GPRS module with Arduino-style microcontroller boards.

✅ Features:

• Arduino UNO compatible header layout
• Quectel M66 GSM/GPRS module with SIM card slot
• u.FL connector for external antenna
• Integrated level shifters for UART signals
• Power supply filtering and ESD protection
• Optimized PCB design for stable communication

🛠️ Status:

• PCB has been fabricated, assembled, and tested
• Board is functional and works as intended except for one major hardware flaw

⚠️ Known Issue in v1.0:

A critical hardware design flaw was identified during post-assembly testing:

• The JP1 jumper must never be soldered or closed.
  If it is connected, the microcontroller will be permanently damaged due to incorrect control over the regulator’s EN (Enable) pin.
• To resolve this in future versions:
  • The JP1 jumper will be removed entirely
  • The EN pin of the voltage regulator will be directly tied to VIN
  • The regulator should not be controlled via a microcontroller pin as it is currently implemented in v1.0

Note

These issues will be addressed in the upcoming hardware revision (v1.1).