I'm designing a PS/2 mouse interface for BASYS 2 FPGA board. As you might know to communicate with a PS/2 mouse you need a protocol, so if I write my VHDL program for the PS/2 protocol and then connect a USB mouse with a PS/2 adapter will it work?

I don't really know what happens inside a mouse but logically I think it shouldn't work or maybe the adapter does all necessary protocol changes? My adapter looks like this PS/2 Male to USB Female Adapter but it's a Microsoft adapter as is my mouse.

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    \$\begingroup\$ These adapters usually only work when they came with your mouse, they require a specific chipset inside the mouse that supports both PS/2 and USB protocols. The mouse can then sense what protocol it should use. \$\endgroup\$ – jippie Jul 15 '14 at 6:20

This absolutely depends on the mouse. I have a USB Microsoft mouse that comes with a similar USB to PS2 adapter. The mouse can sense the difference and reconfigure itself to produce the different protocol but the mouse is marked as such.

99% of the time these adapters are wiring only - there is no intelligence whatsoever within them.

Two things to bear in mind - PS/2 is open collector and the data/clock voltages are 5V. I've been suspicious in the past that these USB/PS2 mice are putting 3.3V on the lines and they get away with it - something to check with a scope!

Edit: Related question which might help you in some way: How to write VHDL program to send command to PS2 device

  • \$\begingroup\$ I've seen the link before but thanks :) \$\endgroup\$ – Ege Jul 15 '14 at 12:32

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