Waveshare Motor Driver HAT User Manual page 6

Motor Driver HAT
The slave address of I2C bus is 7-bits, highest is fixed 1. A5-A0 are hardware
selectable.
This Motor Driver HAT, A5 is connected to ground (0) by default, you can change
resistors of A0-A4 to configure the slave address. If you weld a resistor or short it,
means 1, otherwise 0. The address range from 0x40 to 0x5F.
For example:
1. A5 is 0, A0-A4 are disconnected (don't weld), so they are 0 as well. The final I2C
slave address is 0x40
2. Welding 0Ω resistors to A0-A4 or shorting them, the final I2C slave address is
0x5F. You can use i2cdetect tool to detect i2C devices on Raspberry Pi as below:
execute command: i2cdetect -y 1
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