General advice on how to read a datasheet (I am updating this as I go)

Digital pins

Inverted/Active low/NOT

A pin which is active low is typically designated with a / or an overbar

For example: /CS or CS

A common example is the chip select (/CS) pin on devices with SPI, where the chip select must be low for the SPI on the chip to become active. When it it high, it is idle.