Appendices; Turbo Magellan/Space Mouse - Logitech Magellan/SPACE MOUSE Classic Programmer's Manual

Appendices

Turbo Magellan/SPACE MOUSE

The differences between the standard
Magellan/SPACE MOUSE (SSM) and the Turbo
Magellan/SPACE MOUSE (TSM) are the baud
rates and the data packet formats. The TSM
uses a double-speed internal clock and a
shorter data packet format. The baud rate at
the serial port is also doubled to 19200 baud
(8 bit, no parity and two stop-bits). This allows
the TSM a faster data packet transmission rate
of 18 ms (as compared with 58 ms of the
SSM). Note that the TSM uses the same
command and message formats as the SSM,
which have already been described in this
document.
Communication
Six bits of useful data are coded into a byte.
The equivalent 8-bit value (the first two bits
set to zero plus the six bits of useful data) is
coded in two nibbles, as shown in the table at
right.
Data Structure
Data packets are transmitted from the TSM to
the computer using the structure described
below. Note that this packet structure cannot
be used as a command.
Structure: d <tx1><tx0>
<ty1><ty0>
<tz1><ty0>
<ra1><ra0>
<rb1><rb0>
<rc1><rc0>
<cs1><cs0>\r
<t,r
The data packet contains two
x,y,z,a,b,c
bytes for each of the six input
1,0>
values (x, y, z, a, b and c). Only
the lower six bits of each byte
are used. Each pair of 6-bit
bytes are combined into a 12-
bit value. The high-order six
bits are transmitted first and
the low-order six bits are
transmitted second. In general
the following formula is used to
calculate each of the six inputs:
<t,r input> = <t,r input 1> * 64 +
<t,r input 0> - 2048
6 Bits 8 Bits
0 128
1 65
2 66
3 131
4 68
5 133
6 134
7 71
8 72
9 137
10 138
11 75
12 140
13 77
14 78
15 143
16 80
17 145
18 146
19 83
20 148
21 85
22 86
23 151
24 152
25 89
26 90
27 155
28 220
29 157
30 158
31 95
32 224
33 161
34 162
35 99
36 164
37 101
38 102
39 167
40 168
41 105
42 106
43 171
44 108
45 173
46 174
47 111
48 176
49 113
50 114
51 179
52 116
53 181
54 182
55 119
56 120
57 185
58 186
59 123
60 188
61 125
62 62
63 191
17
2-Nibble
Character
Code (Hex)
80
Ç
41
A
42
B
83
â
44
D
85
à
86
å
47
G
48
H
89
ë
8A
è
4B
K
8C
î
4D
M
4E
N
8F
Å
50
P
91
æ
92
Æ
53
S
94
ö
55
U
56
V
97
ù
98
ÿ
59
Y
5A
Z
9B
¢
DC ▄
9D
¥
9E
₧
5F
_
E0
α
A1
í
A2
ó
63
c
A4
ñ
65
e
66
f
A7
º
A8
¿
69
i
6A
j
AB
½
6C
l
AD
¡
AE
«
6F
o
B0
░
71
q
72
r
B3 │
74
t
B5 ╡
B6 ╢
77
w
78
x
B9 ╣
BA ║
7B
{
BC
╝
7D
}
3E
>
BF
┐