
simulate this circuit – Schematic created using CircuitLab
Figure 1. Common ground for all logic.
I haven't come across that chip before but I'd suggest a layout like this. It avoids any sneak paths between ground and common - such as when programming your MCU through a USB port on your laptop, etc., and is common practice in current measuring applications.
The gain is only 20 so if you want, for example, 3 V out at 30 A then your shunt would need to drop \$ \frac {3~V}{20} = 0.15~V\$ and its resistance would be \$ \frac {0.15~V}{30~A} = 5~m\Omega\$.
Perhaps a better option based on your comment is to use high-side monitoring.

Figure 36 of the datasheet shows a high-side monitor. (They seem to have the battery symbol upside-down.)
High-Side Current Sense with a High-Side Switch
This configuration minimizes the possibility of unexpected
solenoid activation and excessive corrosion (see
Figure 36). In
Figure 36, both the switch and the shunt are on the high side.
When the switch is off, the battery is removed from the load,
which prevents damage from potential shorts to ground, while
still allowing the recirculation current to be measured and
providing for diagnostics. Removing the power supply from the
load for the majority of the time minimizes the corrosive effects
that can be caused by the differential voltage between the load
and ground. When using a high-side switch, the battery voltage
is connected to the load when the switch is closed, causing the
common-mode voltage to increase to the battery voltage. When
the switch is opened, the voltage reversal across the inductive
load causes the common-mode voltage to be held one diode
drop below ground by the clamp diode.