I/O expander for RPI5 to run linuxcnc

Now i want to expand my inputs and outputs in raspberry pi 5, can you suggest me how to expand my i/o and if there is any solution can you also tell me how to configure HAl. I do not want to use MESA board as it is expensive, can someone suggest something cheaper?

Meister's linuxcnc-rio project will do everything you want. Complete working hal & ini Configs are included when building a config. Tango type FPGA boards are supported and quite inexpensive. There are also modules that support different adc chips, spi expanders and a whole host of other chips.
Thread starts here:
forum.linuxcnc.org/18-computer/49142-lin...-ecp5?start=0#271608

There is no really sub $20 solution.
Unless you give a description of your machine, number of axis, number of spindles, number of I/O, whether you have stop and limit switches, whether they are shared or not, what other I/O you need, it's impossible to give you the ini & hal files, even with all that info you will more than likely have to edit yourself.

or the remora project:

forum.linuxcnc.org/18-computer/44828-rem...ernet-nvem-cnc-board
...
and some esp32 projects

we got a w5500 thing on remora also,
this is the cheapest i could build something probably

github.com/cakeslob/RRW_LAB

I may require a minimum of 16 input and 16 output pins, is it available in linuxcnc-rio?

yes, but may I ask what you intend to do with so many IOs?

example via shiftreg:
forum.linuxcnc.org/18-computer/49142-lin...ecp5?start=30#274910

or if you have a bigger FPGA with enough PIN's,
or ....