Hello @ajb2k3

I think you might still be thinking about the wrong module. (I know it's a bit confusing as both these modules are listed on the specs page.)

The Stepmotor Driver Module (HR8825) uses an TCA9554 and not an STM32. So no open source firmware as far as I can see.

Thanks
Felix

I think you may be thinking of the servo module as the ones I have and the product title shows AATMEGA328

the 13.2 uses the STM32

I think you might still be thinking about the wrong module. (I know it's a bit confusing as both these modules are listed on the specs page.)

The Stepmotor Driver Module (HR8825) uses an TCA9554 and not an STM32. So no open source firmware as far as I can see.

Thanks
Felix

Hello @ajb2k3

correct, but @NilZ was asking about the Stepmotor Driver Module (HR8825). Or did I miss something?

Thanks
Felix

Ahh, I sread the 13.2 on the bottom line and thought that was what he was asking about.
However, the firmware is available here: https://github.com/m5stack/stepmotor_module/tree/master/Firmware for stepmotor module/GRBL-Arduino-Library
and you can change the address in grblmain.cpp by editing

#define I2C_ADDR 0x73

to

#define I2C_ADDR 0x71

or any other available i2c address and the address is handled by the atmega328 controller.

correct, but @NilZ was asking about the Stepmotor Driver Module (HR8825). Or did I miss something?

Thanks
Felix

Hello @NilZ

1. apart from the M5Stack color (white vs. black) there is no difference - you can double-check that yourself as for both the schematic link is the same.
2. yes
3. no, the I2C address is fixed to 0x27. There are no dip switches or solder pads to change the I2C address I can see. That said, in the schematic you'll see that the chip doing I2C has three address pins but they are all tied to VCC.

Thanks
Felix

The GRBL has a set of dip switches that are used to change the I2c address from 0x70 to 0x71

https://docs.m5stack.com/en/module/grbl13.2

1. apart from the M5Stack color (white vs. black) there is no difference - you can double-check that yourself as for both the schematic link is the same.
2. yes
3. no, the I2C address is fixed to 0x27. There are no dip switches or solder pads to change the I2C address I can see. That said, in the schematic you'll see that the chip doing I2C has three address pins but they are all tied to VCC.

Thanks
Felix