Min/Max downsampler module
==========================

This module downsamples a data stream by selecting minimum and/or maximum values in each window. The window size can be configured as a generic, allowing any fixed downsampling factor. The module has two operation modes that determine which samples will be preserved from each window and which will be dropped:

- In mode 0, both the minimum and the maximum value of the window are provided to the user after enough input samples are received.
- In mode 1, only either the minimum or the maximum value of the window is provided to the user after enough input samples are received.

Downsampling is performed by asserting ``valid_o`` once every N ``valid_i`` pulses, where N = 2 * ``downsampling_factor_g`` in mode 0 and N = ``downsampling_factor_g`` in mode 1. This difference guarantees that the downsampling factor is respected even though every ``valid_o`` cycle corresponds to two valid values in mode 0 and only one in mode 1.

- In mode 0, when `valid_o` goes high two values are available to the user: `data_o` and `data_min_o`.
- In mode 1, when `valid_o` goes high, only `data_o` should be considered.

Input data is processed during each `valid_i` pulse. It is compared with the largest and smallest values previously found in the same window, updating one of these two variables if required. Comparisons can be set to signed or unsigned at runtime.

Note that in mode 1 the average value of the downsampled stream will be different from the average of the input stream.

Also note that changing `signed_i` or `keep_min_i` during operation of the module should be avoided, as it may cause the selection of an unexpected value in the current downsampling window.

VHDL interface description
--------------------------

.. vhdlentity::
   :file: ../Firmware/Source/modules/minmax_downsampler/hdl/minmax_downsampler.vhd
   :entity: minmax_downsampler