MOUSE(4)
NAME
mouse - serial mouse interface
CONFIG
Serial mice are connected to a serial RS232/V24 dialout
line, see cua(4) for a description.
DESCRIPTION
Introduction
The pinout of the usual 9 pin plug as used for serial mice
is:
pin name used for
2 RX Data
3 TX -12 V, Imax = 10 mA
4 DTR +12 V, Imax = 10 mA
7 RTS +12 V, Imax = 10 mA
5 GND Ground
This is the specification, in fact 9 V suffices with most
mice.
The mouse driver can recognize a mouse by dropping RTS to
low. About 14 ms later the mouse will send 0x4D on the
data line. After a further 63 ms, Microsoft-compatible
mice will send 0x33. Other mice send different values.
The relative mouse movement is sent as dx (positive means
right) and dy (positive means down). Various mice can
operate at different speeds. To select speeds, cycle
through the speeds 9600, 4800, 2400 and 1200 bit/s, each
time writing the two characters from the table below and
waiting 0.1 seconds. The following table shows available
speeds and the strings that select them:
bit/s string
9600 *q
4800 *p
2400 *o
1200 *n
The first byte of a data packet can be used to synchroni-
sation purposes.
Microsoft protocol
The Microsoft protocol uses 1 start bit, 7 data bits, no
parity and one stop bit at the speed of 1200 bits/sec.
Data is sent to RxD in 3-byte packets. The dx and dy
movements are sent as two's-complement, lb (rb) are set
when the left (right) button is pressed:
byte d6 d5 d4 d3 d2 d1 d0
1 1 lb rb dy7 dy6 dx7 dx7
2 0 dx5 dx4 dx3 dx2 dx1 dx0
3 0 dy5 dy4 dy3 dy2 dy1 dy0
Original Microsoft mice only have two buttons. However,
there are some three button mice which also use the
Microsoft protocol. Pressing the third button is reported
by sending a packet with zero movement and no buttons
pressed.
Mousesystems protocol
The Mousesystems protocol uses 1 start bit, 8 data bits,
no parity and two stop bits at the speed of 1200 bits/sec.
Data is sent to RxD in 5-byte packets. dx is sent as the
sum of the two two's-complement values, dy is send as
negated sum of the two two's-complement values. lb (mb,
rb) are cleared when the left (middle, right) button is
pressed:
byte d7 d6 d5 d4 d3 d2 d1 d0
1 1 ? ? ? ? lb mb rb
2 0 dxa6 dxa5 dxa4 dxa3 dxa2 dxa1 dxa0
3 0 dxb6 dxb5 dxb4 dxb3 dxb2 dxb1 dxb0
4 0 dya6 dya5 dya4 dya3 dya2 dya1 dya0
5 0 dyb6 dyb5 dyb4 dyb3 dyb2 dyb1 dyb0
Sun protocol
The Sun protocol uses 1 start bit, 8 data bits, no parity
and two stop bits at the speed of 1200 bits/sec. Data is
sent to RxD in 3-byte packets. dx is sent as single
two's-complement value, dy as negated two's-complement
value. lb (mb, rb) are cleared when the left (middle,
right) button is pressed:
byte d7 d6 d5 d4 d3 d2 d1 d0
1 1 ? ? ? ? lb mb rb
2 0 dx6 dx5 dx4 dx3 dx2 dx1 dx0
3 0 dy6 dy5 dy4 dy3 dy2 dy1 dy0
MM protocol
The MM protocol uses 1 start bit, 8 data bits, odd parity
and one stop bit at the speed of 1200 bits/sec. Data is
sent to RxD in 3-byte packets. dx and dy are sent as sin-
gle signed values, the sign bit indicating a negative
value. lb (mb, rb) are set when the left (middle, right)
button is pressed:
byte d7 d6 d5 d4 d3 d2 d1 d0
1 1 ? ? dxs dys lb mb rb
2 0 dx6 dx5 dx4 dx3 dx2 dx1 dx0
3 0 dy6 dy5 dy4 dy3 dy2 dy1 dy0
FILES
/dev/mouse a commonly used symlink pointing to a mouse
device
SEE ALSO
cua(4) bm(4)