OpenCR

The sensor revision changes the specification

The official manual lists an STM32F746ZGT6 Cortex-M7 processor at 216 MHz, a 105 × 75 mm board and USB, DYNAMIXEL TTL/RS-485, UART, CAN, I2C, SPI and general-purpose interfaces. It explicitly says the MPU9250 was replaced by ICM-20648 in 2020. The newer sensor listing includes gyro and accelerometer functions, while the older one also includes a magnetometer. An older nine-axis description should therefore not be copied onto an unidentified board. [S007]

Power also needs configuration-specific checking. The manual lists USB 5 V or a 5–24 V battery/SMPS input. It specifies a 12 V output maximum of 4.5 A and a 5 V output maximum of 4 A, with a shared 55 W ceiling across those outputs. Their individual maxima should not be added into an unrestricted actuator budget. USB communication alone does not establish enough power for an attached robot. [S007]

Separate board support from the robot application

The documented Arduino route adds ROBOTIS's package index, installs the OpenCR board package, selects the board and selects the actual USB serial port. Linux instructions include USB access rules and historical 32-bit library requirements. The examples refer to old Arduino versions, so they establish the documented workflow rather than a tested recipe for every current IDE and operating system. [S008]

Before uploading, retain the physical board revision, its installed application and the intended robot's firmware pairing. The source tree separates general Arduino support from TurtleBot3 release binaries and loader tools. A successful generic board upload would not verify a complete TurtleBot3 or other robot installation. No host packages or robot firmware were installed during this review. [S001] [S008]

The manual describes two recovery-related procedures that should not be confused. MCU DFU mode uses the Boot button during reset for bootloader work; application recovery uses PUSH SW2 during reset to enter the existing bootloader and download normal firmware. Match the procedure to the problem rather than treating bootloader replacement as a routine application upload. These procedures were read, not exercised on hardware. [S009] [S010]

Hardware files are available; precise terms remain unresolved

The separate hardware archive contains 14 files, including a REVH BOM, Gerber ZIP, OrCAD schematic, DXF outlines and STEP/STL layout models. Its README declares open-source distribution but the inspected archive contains no root license document identifying the specific hardware terms. The firmware repository's Apache-2.0 license does not automatically answer that question for a different repository. File availability and confirmed reuse rights are recorded separately here. [S003] [S005] [S006]

The hardware BOM and drawing files were inventoried, but their component rows, geometry and fabrication completeness were not validated. A current complete budget remains unknown, including the board, supply, cables, host and selected robot's actuators. No board was fabricated, firmware flashed, sensor calibrated or robot operated for this profile. [S006] [S007] [S008]