ps-2 mouse interfacing.htm

PS2 mouse very good info

              <TD>
                <CENTER>Bit 2</CENTER></TD>
              <TD>
                <CENTER>Bit 1</CENTER></TD>
              <TD>
                <CENTER>Bit 0</CENTER></TD></TR></TBODY></TABLE>
          <TABLE cellSpacing=0 cols=8 cellPadding=0 width="100%" border=1>
            <TBODY>
            <TR>
              <TD>
                <CENTER><FONT face=Arial,Helvetica><FONT size=-1>Y 
                overflow</FONT></FONT></CENTER></TD>
              <TD>
                <CENTER><FONT face=Arial,Helvetica><FONT size=-1>X 
                overflow</FONT></FONT></CENTER></TD>
              <TD>
                <CENTER><FONT face=Arial,Helvetica><FONT size=-1>Y sign 
                bit</FONT></FONT></CENTER></TD>
              <TD>
                <CENTER><FONT face=Arial,Helvetica><FONT size=-1>X sign 
                bit</FONT></FONT></CENTER></TD>
              <TD>
                <CENTER><FONT face=Arial,Helvetica><FONT size=-1>Always 
                1</FONT></FONT></CENTER></TD>
              <TD>
                <CENTER><FONT face=Arial,Helvetica><FONT size=-1>Middle 
                Btn</FONT></FONT></CENTER></TD>
              <TD>
                <CENTER><FONT face=Arial,Helvetica><FONT size=-1>Right 
                Btn</FONT></FONT></CENTER></TD>
              <TD>
                <CENTER><FONT face=Arial,Helvetica><FONT size=-1>Left 
                Btn</FONT></FONT></CENTER></TD></TR></TBODY></TABLE></TD></TR>
      <TR>
        <TD><FONT face=Arial,Helvetica><FONT size=-1>Byte 2</FONT></FONT></TD>
        <TD>
          <TABLE cellSpacing=0 cols=1 cellPadding=0 width="100%" border=1>
            <TBODY>
            <TR>
              <TD>
                <CENTER><FONT face=Arial,Helvetica><FONT size=-1>X 
                Movement</FONT></FONT></CENTER></TD></TR></TBODY></TABLE></TD></TR>
      <TR>
        <TD><FONT face=Arial,Helvetica><FONT size=-1>Byte 
        3&nbsp;</FONT></FONT></TD>
        <TD>
          <TABLE cellSpacing=0 cols=1 cellPadding=0 width="100%" border=1>
            <TBODY>
            <TR>
              <TD>
                <CENTER><FONT face=Arial,Helvetica><FONT size=-1>Y 
                Movement</FONT></FONT></CENTER></TD></TR></TBODY></TABLE></TD></TR>
      <TR>
        <TD><FONT face=Arial,Helvetica><FONT size=-1>Byte 4</FONT></FONT></TD>
        <TD>
          <TABLE cellSpacing=0 cols=8 cellPadding=0 width="100%" border=1>
            <TBODY>
            <TR>
              <TD>
                <CENTER><FONT face=Arial,Helvetica><FONT size=-1>Always 
                0</FONT></FONT></CENTER></TD>
              <TD>
                <CENTER>Always 0</CENTER></TD>
              <TD>
                <CENTER>5th Btn</CENTER></TD>
              <TD>
                <CENTER>4th Btn</CENTER></TD>
              <TD>
                <CENTER>Z3</CENTER></TD>
              <TD>
                <CENTER>Z2</CENTER></TD>
              <TD>
                <CENTER>Z1</CENTER></TD>
              <TD>
                <CENTER>Z0</CENTER></TD></TR></TBODY></TABLE></TD></TR></TBODY></TABLE>Z0-Z3 
    is a 2's complement number which represents the amount of movement that has 
    occurred since the last data report.&nbsp; Valid values range from -8 to +7. 
    <BR>4th Btn: 1 = 4th mouse button is pressed; 0 = 4th mouse button is not 
    pressed. <BR>5th Btn: 1 = 5th mouse button is pressed; 0 = 5th mouse button 
    is not pressed.</BLOCKQUOTE></BLOCKQUOTE>You may have seen mice with two 
scrolling wheels--one vertical and the other horizontal.&nbsp; These mice use 
the Microsoft Intellimouse data packet format as described above.&nbsp; If the 
vertical wheel is scrolled upward, the Z-counter is incremented by one and if 
that wheel is scrolled down, the Z-counter is decremented by one.&nbsp; This is 
normal operation for a scrolling wheel.&nbsp; However, if the <I>horizontal</I> 
wheel is scrolled right, the Z-counter is incremented by <I>two</I> and if it is 
scrolled left, the Z-counter is decremented by <I>two</I>.&nbsp; This seems like 
an odd way to implement the second scrolling wheel, but it works since the 
placement of the two wheels make it impossible to use both of them at the same 
time (and if you try to trick the software and use both at the same time, it 
will ignore the horizontal wheel.) 
<P><B>Command Set:</B> </P>
<P>The following is the set of command accepted by the standard PS/2 mouse. 
&nbsp;If the mouse is in Stream mode, the host should disable data reporting 
(command F5h) before sending any other commands. </P>
<UL>
  <LI>FFh (Reset) - The mouse responds to this command with "acknowledge" (FAh) 
  then enters Reset Mode. 
  <LI>FEh (Resend) - The host sends this command whenever it receives invalid 
  data from the mouse. The mouse responds by resending the last<A 
  href="http://www.computer-engineering.org/ps2mouse/#Footnotes">(2)</A> 
  packet<A 
  href="http://www.computer-engineering.org/ps2mouse/#Footnotes">(3)</A> it sent 
  to the host.&nbsp;&nbsp; If the mouse responds to the "Resend" command with 
  another invalid packet, the host may either issue another "Resend" command, 
  issue an "Error" command, cycle the mouse's power supply to reset the mouse, 
  or it may inhibit communication (by bringing the Clock line low).&nbsp; The 
  action taken depends on the host. 
  <LI>F6h (Set Defaults) - The mouse responds with "acknowledge" (FAh) then 
  loads the following values:&nbsp; Sampling rate = 100, Resolution = 4 
  counts/mm, Scaling = 1:1, Disable Data Reporting.&nbsp; The mouse then resets 
  its movement counters and enters stream mode. 
  <LI>F5h (Disable Data Reporting) - The mouse responds with "acknowledge" (FAh) 
  then disables data reporting and resets its movement counters.&nbsp; This only 
  effects data reporting in Stream mode and does not disable sampling.&nbsp; 
  Disabled stream mode funcions the same as remote mode. 
  <LI>F4h (Enable Data Reporting) - The mouse responds with "acknowledge" (FAh) 
  then enables data reporting and resets its movement counters.&nbsp; This 
  command may be issued while the mouse is in Remote Mode (or Stream mode), but 
  it will only effect data reporting in Stream mode. 
  <LI>F3h (Set Sample Rate) - The mouse responds with "acknowledge" (FAh) then 
  reads one more byte from the host.&nbsp; The mouse saves this byte as the new 
  sample rate. After receiving the sample rate, the mouse again responds with 
  "acknowledge" (0xFA) and resets its movement counters.&nbsp; Valid sample 
  rates are 10, 20, 40, 60, 80, 100, and 200 samples/sec. 
  <LI>F2h (Get Device ID) - The mouse responds with "acknowledge" (FAh) followed 
  by its device ID (00h for the standard PS/2 mouse.)&nbsp; The mouse should 
  also reset its movement counters. 
  <LI>F0h (Set Remote Mode) - The mouse responds with "acknowledge" (FAh) then 
  resets its movement counters and enters remote mode. 
  <LI>EEh (Set Wrap Mode) - The mouse responds with "acknowledge" (FAh) then 
  resets its movement counters and&nbsp; enters wrap mode. 
  <LI>ECh (Reset Wrap Mode) - The mouse responds with "acknowledge" (FAh) then 
  resets its movement counters and enters the mode it was in prior to wrap mode 
  (Stream Mode or Remote Mode.) 
  <LI>EBh (Read Data) - The mouse responds with acknowledge (FAh) then sends a 
  movement data packet. This is the only way to read data in Remote Mode.&nbsp; 
  After the data packets has been successfully sent, it resets its movement 
  counters. 
  <LI>EAh (Set Stream Mode) - The mouse responds with "acknowledge" then resets 
  its movement counters and enters steram mode. 
  <LI>E9h (Status Request) - The mouse responds with "acknowledge" then sends 
  the following 3-byte status packet (then resets its movement counters.):&nbsp; 

  <UL>
    <LI>&nbsp; 
    <TABLE cellSpacing=0 cellPadding=0 width=650 border=0>
      <TBODY>
      <TR>
        <TD><BR><FONT face=Arial,Helvetica><FONT size=-1>Byte 
          1&nbsp;</FONT></FONT></TD>
        <TD>
          <TABLE cols=8 cellPadding=0 width="100%" border=0>
            <TBODY>
            <TR>
              <TD>
                <CENTER>Bit 7</CENTER></TD>
              <TD>
                <CENTER>Bit 6</CENTER></TD>
              <TD>
                <CENTER>Bit 5</CENTER></TD>
              <TD>
                <CENTER>Bit 4</CENTER></TD>
              <TD>
                <CENTER>Bit 3</CENTER></TD>
              <TD>
                <CENTER>Bit 2</CENTER></TD>
              <TD>
                <CENTER>Bit 1</CENTER></TD>
              <TD>
                <CENTER>Bit 0</CENTER></TD></TR></TBODY></TABLE>
          <TABLE cellSpacing=0 cols=8 cellPadding=0 width="100%" border=1>
            <TBODY>
            <TR>
              <TD>
                <CENTER><FONT face=Arial,Helvetica><FONT size=-1>Always 
                0</FONT></FONT></CENTER></TD>
              <TD>
                <CENTER><FONT face=Arial,Helvetica><FONT 
                size=-1>Mode</FONT></FONT></CENTER></TD>
              <TD>
                <CENTER><FONT face=Arial,Helvetica><FONT 
                size=-1>Enable</FONT></FONT></CENTER></TD>
              <TD>
                <CENTER><FONT face=Arial,Helvetica><FONT 
                size=-1>Scaling</FONT></FONT></CENTER></TD>
              <TD>
                <CENTER><FONT face=Arial,Helvetica><FONT size=-1>Always 
                0</FONT></FONT></CENTER></TD>
              <TD>
                <CENTER><FONT face=Arial,Helvetica><FONT size=-1>Left 
                Btn</FONT></FONT></CENTER></TD>
              <TD>
                <CENTER><FONT face=Arial,Helvetica><FONT size=-1>Middle 
                Btn</FONT></FONT></CENTER></TD>
              <TD>
                <CENTER><FONT face=Arial,Helvetica><FONT size=-1>Right 
                Btn</FONT></FONT></CENTER></TD></TR></TBODY></TABLE></TD></TR>
      <TR>
        <TD><FONT face=Arial,Helvetica><FONT size=-1>Byte 2</FONT></FONT></TD>
        <TD>
          <TABLE cellSpacing=0 cols=1 cellPadding=0 width="100%" border=1>
            <TBODY>
            <TR>
              <TD>
                <CENTER><FONT face=Arial,Helvetica><FONT 
                size=-1>Resolution</FONT></FONT></CENTER></TD></TR></TBODY></TABLE></TD></TR>
      <TR>
        <TD><FONT face=Arial,Helvetica><FONT size=-1>Byte 
        3&nbsp;</FONT></FONT></TD>
        <TD>
          <TABLE cellSpacing=0 cols=1 cellPadding=0 width="100%" border=1>
            <TBODY>
            <TR>
              <TD>
                <CENTER><FONT face=Arial,Helvetica><FONT size=-1>Sample 
                Rate</FONT></FONT></CENTER></TD></TR></TBODY></TABLE></TD></TR></TBODY></TABLE>
    <P><I>Right, Middle, Left Btn</I> = 1 if button pressed; 0 if button is not 
    pressed. <BR><I>Scaling</I> = 1 if scaling is 2:1; 0 if scaling is 1:1. (See 
    commands E7h and E6h) <BR><I>Enable</I> = 1 if data reporting is enabled; 0 
    if data reporting is disabled. (See commands F5h and F4h) <BR><I>Mode</I> =