In Table 8.3 of the datasheet, we will be powering the MCU with coin cell batteries, it recommends a 10-µF cap to the ground from VDDS.
It recommends 0.1µF on each of the VDDS which is connected to our battery positive, so we have 4 x 0.1 = 0.4µF plus a 4.7µF and 1µF
Should we add another cap to make the total 10µF?
Can you clarify what is meant by slew rate? Is this in reference to the fall time of a digital output including SPI communication?
Due to the battery performance deteriorating at its end of life, the 10µF acts as a power buffer storage for when an output changes states creating an increase in current draw? (without the capacitor the battery could struggle to meet the demand causing the output rise time to increase?)