1 $Id: README,v 1.2 2003-10-23 21:20:34 vladimir Exp $
2
3 The "New MoteNIC"
4 -----------------
5
6 21 Feb 2003
7
8
9 The "mote" directory contains the source for the New MoteNIC. This
10 README file describes its design, and how to extend it.
11
12 The first thing to remember is that "MoteNIC" is really a misnomer.
13 This software is a collection of daemons that give Linux-based
14 programs access to various functions of the Mote. Originally, the
15 only one of these functions was sending and receiving packets, hence
16 the name "MoteNIC". However, there are now other functions, such as
17 querying the mote for values of its sensors, and performing time
18 synchronization between the Linux clock and the Mote's clock.
19
20 Communication between the Linux host and the Mote is performed using
21 the "Host-Mote Protocol". This is a simple protocol with a
22 fixed-length header followed by variable length data, and is mainly
23 responsible for framing messages over the serial port. Host-Mote
24 protocol messages have a "type" associated with them, describing which
25 module (NIC, sensor, configuration, synchronization, etc.) should
26 process the packet.
27
28 The host-mote protocol is defined in the header file:
29 tos/tinyos-1.x/tos/system/host_mote.h
30
31 The contents of the variable-length data portion of a Host-Mote packet
32 depends on the module. For example:
33
34 -- For NIC-type packets, the data is either a flow-control packet
35 (request to send, clear to send...), or a TOS_Msg that was either
36 just received on the radio or which is being given to the mote to
37 send on the radio.
38
39 -- For Configuration-type packets, the data is a structure describing
40 the configuration of the mote (its POT value, Group ID, etc.)
41
42 -- For Sensor-type packets, the data is a series of sensor values from
43 the mote's ADC, or a request to configure the ADC.
44
45 The details of each of these "sub-protocols" that runs over the
46 Host-Mote protocol are documented in other README files in this
47 directory.
48
49
50 The Design of the Software
51 --------------------------
52
53 On the Linux side, the implementation of the mote software is now
54 distributed into multiple modules, each of which is responsible for
55 one function.
56
57 The "master" module, hostmoted, is the only daemon that deals directly
58 with the serial port. It is responsible for the low-level handling of
59 the host-mote protocol -- that is, framing and packetizing the
60 incoming serial stream. It then feeds the hostmote packets to other
61 daemons, each of which can open hostmoted's device file and tell it
62 what kind of hostmote packets it wants (e.g. NIC, Sensor, etc.).
63
64 Extending the Host-Mote protocol consists of the following steps:
65
66 1- Define a new "op type" in the host-mote protocol header.
67
68 2- Add code to the mote-side (transceiver) app that knows how to deal
69 with this op.
70
71 3- Create a new daemon to handle your protocol on the Linux sid,
72 similar to the "motenic" and "motesens" daemons (in the nic and sens
73 directories, respectively). Each of these daemons gets packets of a
74 particular op-type from hostmoted and does something useful with them.
This page was automatically generated by the
LXR engine.
Visit the LXR main site for more
information.
