CNC HAT
CNC HAT Drives 3 stepper motors. It uses TI DRV8825 drivers with 1:32 microsteps. Onboard Arduino compatible ATmega328 microcontroller interprets GCODE commands come from Raspberry Pi's UART port. CNC HAT comes with GRBL preflashed, which can be modified via ICSP pins. 6 Endstop connectors, 3 function connectors + buttons and a head connector with spindle pwm, dir and probe pin is connected to the microcontroller. The I2C port is directly connected to Raspberry Pi's I2C1 line, so you can add displays, sensors and servo drivers to the board easily.
Combined features on CNC HAT makes it easy to bring your mechanical projects to life.
TI DRV8825
3x TI DRV8825 drives 9-24V 1.5A bipolar stepper motors. Microstepping ratio is set to 1:32 steps.
ATmega328
Onboard microcontroller and crystal oscillator precisely control your equipment. It is preloaded with GRBL firmware and can be updated by the user.
Panasonic Capacitors
Panasonic 50V 330uF 105C Electrolytic capacitors stabilize  and pump required power to the drivers.
Endstop Connections
2 Endstops per X, Y and Z channels are supplied. Endstops on channels are interconnected.
Control Buttons & Ports
There are ports and buttons for Reset / Abort, Resume, Feed / Hold inputs. You can either use buttons or ports to control firmware.
Head Port
Spindle PWM, Spindle Dir, Probe and GND pins are included in the head port.
I2C Port

I2C Port is directly connected to the Raspberry Pi's I2C1 bus. It is easy to add displays, sensors or external drivers to the board.

Fuse
A high quality 12A fuse is installed to protect your equipment.
HAT Standard EEPROM
A write protected EEPROM is configured and connected to I2C0 bus for Raspberry Pi HAT standard compliance. Your OS will configure required ports automatically if it supports.
Spacers
Spacers will keep your CNC HAT stable. We also provided a small screwdriver for spacer and terminal screws.
Component detail connections and datasheets are shared here.
TI DRV8825 Stepper Motor Driver
There are 3 onboard DRV8825 on CNC HAT.
  • Voltage: Between 9 and 24 Volts.
  • Current: Limited to 1.5 Amps on CNC HAT.
  • Resolution: 1:32 Microsteps set.
Drivers are controlled by onboard microcontroller. They aren't connected to the Raspberry Pi directly, for best performance.
I2C Port
There is 1 I2C Port.
  • I2C Port: 1 Port with 3.3V, GND, SDA and SCL pins. It is connected directly to the Raspberry Pi's I2C1 bus.
Please do not overload 3.3V output more than 20mA. The power output is for low power sensors.
Drivers and samples for Raspbian will be shared soon on GitHub.