PSIF Linux driver for PS/2

The circuit below is only needed for regular PS/2 mouses which in most cases must have 5 volt for the optical stuff to work. Many keyboards and USB-to-PS/2 adapters will only need 3.3 volt, which is the default on STK1000 PS/2 ports.

USB-to-PS/2 adapters will need a hack where you power the adapter with a 5 volt regulator, but the I/O lines can be 3.3 volt.

There is now released an appnote by Atmel about using the PSIF as a PS/2 driver in Linux.

See the attached PDF file for some insight into the PS/2 protocol.

Some URLs with good information about the PS/2 protocol:

Linux kernel patches

The patches below are made against Linux kernel version 2.6.24.atmel.1.

Example level-shifting circuit

Attachment	Action	Size	Date	Who	Comment
0001-Add-PSIF-platform-resources-to-device-code-and-board.patch	manage	3.5 K	26 Feb 2008 - 07:40	HansChristianEgtvedt	Patch to add the machine code to at32ap700x
pca9306.png	manage	14.8 K	22 Aug 2007 - 17:18	JohnVoltz	Level-shifting circuit
psif.c	manage	1.8 K	11 Sep 2007 - 01:20	JohnVoltz	Test Program
CR0109_PS2_Controller.pdf	manage	739.8 K	11 Sep 2007 - 01:21	JohnVoltz	PS/2 Protocol
0003-PS-2-serio-driver-for-AVR32-devices.patch	manage	13.0 K	26 Feb 2008 - 07:42	HansChristianEgtvedt	Patch to add at32psif serio driver to the input sub-system
0002-Wire-up-PSIF-device-0-and-1-for-the-ATSTK1002-ATSTK.patch	manage	3.3 K	26 Feb 2008 - 07:41	HansChristianEgtvedt	Patch to add the psif stuff in STK1000 board code, configurable with kbuild
psif-2.6.22-git.patch	manage	17.3 K	22 Aug 2007 - 17:19	JohnVoltz	Patch for kernel 2.6.22-git