Primax ic?

[e44-72]

Hello

I've opened an old Compaq mouse (with an old ball not an optical mouse), its not even got a usb on it but instead the old connection you used to plug mouses in.

In it is an 18 pin dil IC and I would like to know what it is but I can't seem to find any info on it.
The full numbering on it is:

PRIMAX 9429
EICI 029500

Anyone know what the IC is and what it does?

Thank you for any comments

 

[Sceadwian]

It records ticks from the optical encoders attached to the wheels that are driven by the mouse ball and converts them to the PS2 protocol that drives mice. Typically it has some modest logic in it as Ps2 mice were generally programmable to a certain degree between absolute and incremental output.

 

[e44-72]

Thanks for your reply, I've wanted to know what it is for while, so thank you

 

[Will D]

Hi Sceadwian ,
What I know about this IC is that it is used for production and replacement.Please elaborate bit more about these chips.I am new to electronics.
Thanks

 

[Sceadwian]

New or old to electronics Will D you're asking about specific types of chips of which I have no familiarity outside of course functioning, you'll need to search out the information you require on your own.

 

[Nigel Goodwin]

It's most probably a programmed microcontroller, or a custom IC - in either case there's almost certainly no informationm available about it - but what would be the point anyway?, it's a specific mouse chip, that's all it can be used for.