BQ24050: Need external host to generate signal to trigger the ISET2 to switch to a different charging current?

Hi Support,

For BQ24050, when connected to a USB port or a DC adapter, it seems like it still requires an external host to generate signal to trigger the ISET2 to switch to a different charging current (fast charge current/500mA).
Likewise, for BQ24040, a drive logic circuit is needed to switch the charging current as shown in the datasheet.

Need your help to confirm that an external signal is required for both BQ24040 and BQ24050, as my design presently does not have a drive logic/host/micro-controller to toggle ISET2 or is there a separate circuit out there that can do this?
Also, if I tie ISET2 to permanently charge at 500mA, what is the consequences when a USB port supporting 100mA max is connected to my device?

Thanks.