Hardware - IRNAS/grbl_stm32 GitHub Wiki

MCU Board

The STM32 Nucleo board provides an affordable and flexible way for users to try out new ideas and build prototypes.

nucleo picture

Our choice was NUCLEO-F411RE, with features:

  • STM32 microcontroller with LQFP64 package
  • Arduino Uno Revision 3 connectivity
  • mbed-enabled (http://mbed.org)
  • On-board ST-LINK/V2-1 debugger/programmer with SWD
  • Flexible board power supply
  • USB re-enumeration capability: three different interfaces supported on USB
    • Virtual Com port
    • Mass storage
    • Debug port
  • Supported by wide choice of Integrated Development Environments (IDEs)

Arduino GRBL Driver

Because Nucleo board has Arduino compatible connectors for shields, it was easy to add standard GRBL shield as the driver for stepper motors. More about this shield can be found on this LINK.

grbl shield pic

ST Stepper Driver

Nucleo board can also be used with ST Stepper motor driver expansion board. The X-NUCLEO-IHM01A1 is a stepper motor driver expansion board based on the L6474. It provides an affordable and easy-to-use solution for driving a stepper motor with STM32 Nucleo. The advanced current control of the L6474 and a complete set of protection features offer high levels of both performance and robustness. The X-NUCLEO-IHM01A1 is compatible with the Arduino UNO R3 connector and supports the addition of other boards which can be stacked to drive up to three stepper motors with a single STM32 Nucleo board. Because one expansion board can drive one motor, three of them are required for a three axis machine. Out of the box, each board is configured to be the sole device. Some solder tags ( tiny, zero value, SMC resistors ) need to be moved on each board to connect them for stacking one on the other. Some hacking is needed to stack more than 3 but is possible.

These boards are supposed to handle 3A RMS motor current but go into thermal shutdown if pushed that hard ( this is non-destructive ). A small 40mm can be mounted on the end of stack to provide some forced air flow. Under these conditions they will provide full rated current to the motors. A low profile aluminium heat sink can also be glued on the underside of each board ( this is the heat dissipation path, not the top of the chip ).

st shield pic

Depending on project configuration only some of the hardware is needed