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myCobot 280 Lab

ATOM controller board

The ATOM is an M5Stack ATOM Matrix. It plugs into a socket at the end of the arm. It is on the servo bus, so it can control the servos directly.

ATOMESP32-PICO-D4LED matrix G27button G39IMU MPU6886 G21 / G25IR LED G12USB serial 115.2k … 1.5M3V3G22servo bus TXG19servo bus RXG23freeG33freeG21IMU SCLG25IMU SDA5VGNDGND5VG26G32Grove (HY2.0-4P)USB-CBlue: the servo bus pins, verified on this arm (G19 RX, G22 TX).The pins plug into the arm socket; the matrix faces out of the arm.

Chip

Section titled “Chip”
Item Value
Chip ESP32-PICO-D4, revision v1.1
CPU 2 × 240 MHz (Xtensa)
Flash 4 MB, embedded
Radio WiFi 2.4 GHz and Bluetooth
MAC address e8:6b:ea:31:4c:f4
WiFi address 192.168.1.107 on the home network (DHCP; check the status log)

Pins

Section titled “Pins”
Function Pin Notes
Servo bus RX G19 Verified with the bus probe.
Servo bus TX G22 Verified. The ATOM does not receive its own transmissions.
LED matrix (25 × SK6812) G27 Keep the brightness low (the firmware uses 20/255).
Button (under the matrix) G39 Active low.
IMU (MPU6886, I²C 0x68) SDA G25, SCL G21 ±8 g and ±2000°/s in the firmware.
IR LED G12 Not used.
Header (free) G23, G33
Grove port G26, G32

The socket in the arm

Section titled “The socket in the arm”

Elephant’s documentation calls this socket function interface group 6.

USB-C opening(the ATOM's own port)Grove (HY2.0-4P)5V0GND3V3G22G19G23G33◯ servo bus: G22 TX, G19 RX.Elephant's docs list them as general I/O; here they are the bus.

The arm end also has a 3-pin side port for a gripper (Elephant’s adaptive gripper). The gripper servo is probably on the same bus as ID 7. This is why the stock firmware pings ID 7. See Gripper.

USB

Section titled “USB”

The ATOM’s USB-serial chip reports as FTDI 0403:6001 (vendor “Hades2001”, serial A952DE0075). On macOS it is /dev/cu.usbserial-A952DE0075.

Condition USB connects Notes
ATOM out of the arm Yes Use this to flash over USB.
ATOM in the arm, 12 V on No
ATOM in the arm, 12 V off Yes Do not use. The USB port then supplies the servos (4.4–5.4 V).
  • Flash and read at 115 200 baud. Reads at 250 and 750 kbaud corrupted data.
  • After the first USB flash, update the firmware over WiFi (OTA). See Build, flash and update.

Firmware

Section titled “Firmware”
Firmware Status
Elephant stock firmware v7.2 Backed up. See Stock firmware backup.
atom_controller Installed. See Controller firmware.
atom_probe Diagnostic firmware. See Bus probe firmware.

In the arm, the LED matrix faces out. It shows the firmware state:

Controller firmware: holding

See LED matrix signals.