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Last modified on 27 January 2016, at 12:27

SYMBiFACE II:PS/2 mouse

Revision as of 12:27, 27 January 2016 by Arnoldemu (Talk | contribs) (→‎Usage)

This is the documentation about the PS/2 mouse connector of the SYMBiFACE II expansion card.

Ports

  • #FD10 (read only) read mouse status

Usage

Status byte
Bit 76543210
Use mmDDDDDD
 
m: Mode
D: Use-Data
 
If read and...

m = 00 -> no more data available, you can stop reading the status for a while
m = 01 -> D = X offset (signed); you will receive positive values, if the user
                                 is moving the mouse to the right
m = 10 -> D = Y offset (signed); you will receive positive values, if the user
                                 is moving the mouse upwards
m = 11 -> D[bit5] = 0 -> D[bit0]   = left button
                         D[bit1]   = right button
                         D[bit2]   = middle button
                         D[bit3]   = forward button
                         D[bit4]   = backward button
          D[bit5] = 1 -> D[bit0-4] = scroll wheel offset (signed)

If m was not 00, then you should read the port again until you receive m=00. If you don't receive a status for the mouse buttons, the last status is still valid.

Example:

Pressing left button only and releasing it will show &c1, one or more zeros and then &c0. If you press and hold down left button you will see &c1, and lots of zeros until you release then it shows &c0.

The hardware will only give you the actual data that has changed, so if only moving left you will only get X offset values and no Y offset or button values.

See also