m5stack INA226AIDGSR ATOMIC Motion Base v1.2 with Power Monitor

AI context

Dense context for pasting into a model prompt — addresses, pinout, voltages, tolerances and the vendor's reference circuit.

PART: M5Stack Atomic Motion Base v1.2, SKU A090-V12, a 75.4 x 24.0 x 20.7 mm servo and DC-motor drive base for the Atom series, built around an STM32F030F4P6 (TSSOP-20) that exposes itself to the Atom as an I2C slave at 0x38. The headline part in the vendor's own title is the INA226AIDGSR current/voltage monitor that watches the battery; the rest of the power path is an RZ7899 motor driver, an ETA9740 charger and a DW01-A single-cell protection IC, and the pack is a removable 18350 cell at 900 mAh.
ADDRESSES: the base's controller answers I2C at 0x38 on the Atom's bus (I2C_SCL on pad 2, I2C_SDA on pad 4). The vendor does not publish the INA226's own bus address, so it is not recorded here.
REGISTERS at 0x38: 0x00-0x03 servo angle, one byte MSB, 0-180 degrees, read/write, channel 1-4; 0x10, 0x12, 0x14, 0x16 servo pulse width, two bytes MSB, 500-2500 us, read/write; 0x20-0x21 motor speed, one byte MSB, -127 to 127, read/write for motor 1 and 2.
PINOUT: the vendor numbers the Atom interface 1-9, odd pins in one column and even pins in the other, pin 1 unpaired: 1 = 3V3, 2 = I2C_SCL, 3 = PORT.C, 4 = I2C_SDA, 5 = PORT.C, 6 = 5V, 7 = PORT.B, 8 = GND, 9 = PORT.B. PORT.B and PORT.C are the base's two HY2.0-4P sensor sockets; the vendor's table names only the port on pads 3, 5, 7 and 9, not which of the port's two signal wires each pad reaches, so this entry does not assign a wire colour to them.
STM32 PIN MAP: PA10 = I2C SDA, PA9 = I2C SCL, PA4 = M1F, PB1 = M1R (DC motor 1 forward/reverse), PA6 = M2F, PA7 = M2R (motor 2), PA0 = Servo3, PA1 = Servo1, PA2 = Servo4, PA3 = Servo2 - the servo channels are not in numeric order on the port pins. A 4-pin SWD header (J3: 3V3, SWDIO, SWCLK, GND) is on the board for direct firmware work, and the STM32F030F4P6's own pins are BOOT0 1, PF0-OSCI 2, PF1-OSCO 3, NRST 4, VDDA 5, PA0-PA7 6-13, PB1 14, VSS 15, VDD 16, PA9 17, PA10 18, PA13/DIO 19, PA14/DCK 20.
SUPPLY: 5 V on pad 6 from the host Atom or through a Grove socket for charging, with a 18350 900 mAh cell; charge cut-off 4.14 V, discharge cut-off 2.5 V, charging current 5 V at 1.18 A, standby current 4.04 V at 40.97 uA with the switch on. Charger components per the schematic: ETA9740 with a 3.3 uH/4012 inductor L1, R2 150 k on ISET, C1/C3/C4/C5 marked 106 (10 uF) and C2 marked 475 (4.7 uF); the STM32 has C6 marked 104 (0.1 uF) and the 3V3 rail has its own decoupling.
LIMITS: overload protection trips at 5 V at 5 A; full-load steering current 3 A; peak current 1 A per motor channel and 0.4 A per servo channel. Operating temperature 0 to 40 C. Logic level on the I2C lines and the 3V3 pad is 3.3 V, matching the Atom.
TRAPS: (1) The base must be switched ON before it will charge - the vendor states this explicitly for both the host-cable and Grove-5V charging paths. (2) Servo channels 1-4 map to PA1, PA3, PA0, PA2 in that order, so wiring by pad order would run the wrong axis. (3) The battery is a removable 18350; the DW01-A protection and the INA226 monitor are separate chips, so the monitor readings are the reference for battery state, not the protection IC. (4) Motor speed registers are signed, -127 to 127, not 0-255. (5) The base is an Atom-shape board: its 3V3 pad is fed from the Atom, and the two Grove ports' remaining pins come from the base's own rails, not from the Atom's pins.