Increasing scan time in Host test firmware

In the host test firmware, you can be a central device then you can device whichever connection parameters you want.

Please take a look at the readme file which comes with the examples.
"The host_test project implements a pure Bluetooth low energy network processor for use with an external microcontroller or a PC software application such as BTool. Host Test supports all GAP roles: Central, Peripheral, Broadcaster and Observer in addition to multi-role combinations of these roles"