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9 The control unit broadcasts data packets across the track.
10 The packets are 9 bytes long, and the structure is the following:
12 0x55 packet_type data_byte1..6 crc
14 The Ole Seeberg's interface adds 0x05 (05 = O.S. :-) after each packet.
15 This byte can be safely ignored.
17 There can be noise on the track, so sometimes the packets are received
18 by a reader with an incorrect checksum. Those should be discarded.
20 The bus reader apparently does not report packets which are sent by
28 Format: 0x55 0xAA N1 N2 0xF0 0xF0 0xF0 0xF0 CRC
30 Sent twice after the car crosses the finish line. This is a message
31 to the car instructing it to send its ID after the given delay.
32 The delay is the ratio of the N1 and N2 numbers. No need to handle
33 this, it is for cars, not race management.
35 N1, N2 - fraction specifiying the bus free time. My Pit box with 020 firmware
36 sends the first packet with 0x0C 0x06, and the second one with
40 55 AA 0C 06 F0 F0 F0 F0 7B
41 55 AA 18 06 F0 F0 F0 F0 93
44 0xCC - car programming
45 ----------------------
46 Format: 0x55 0xCC CTRL 0xFE 0xFF 0xFF 0xFF 0xFF CRC
48 Sent twice when matching the car to the particular controller.
53 Bits 2-0 - number of the controller (starting from 0)
61 Format: 0x55 0xD0 0xFF N1 N2 0xAA 0xAA 0xAA CRC
63 N1, N2 forms the ratio, probably used as a challenge for car control units
66 55 D0 FF 0A 05 AA AA AA AD
71 Format: 0x55 0xD3 P0-P5 CRC
73 Sent after passing the start/finish line for the first time in a race
74 and then every 300 ms.
76 P0-P5: one byte for each position, starts with the leader.
77 0xFF means there is no car on this position (for example,
78 when not all cars have passed the start line)
79 Bit 7 - 1 if the car is more than 15 laps behind the leader
80 Bits 6-3 - number of laps behind the leader (0-15, set to 0
81 when bit 7 is set to 1)
82 Bits 2-0 - vehicle number (0-5)
85 55 D3 81 FF FF FF FF FF 2C
90 Format: 0x55 0xD4 ID R1 R2 MS T1 T2 CRC
92 Sent after passing the finish line and then every 300 ms.
93 Lap count and last lap time of the specified vehicle.
96 R1: Round number - higher byte
97 R2: Round number - lower byte (bit 0 is always zero)
100 Bit 3 - least significant bit of T1
103 Bit 0 - least significant bit of R2
104 T1: Lap time - higher byte (bit 0 is always zero)
105 T2: Lap time - lower byte
107 So the lap number is 256*R1 + R2 + MS & 0x01, and the time is
108 256*T1 + (MS & 0x08 ? 1 : 0)
111 55 D4 01 00 00 01 00 00 59 (round 1 - after crossing the start line)
112 55 D4 01 00 02 08 00 E8 32 (round 2)
113 55 D4 01 00 02 0D 00 B6 3C (round 3)
114 55 D4 01 00 04 0C 04 98 69 (round 4)
119 Format: 0x055 0xD5 DI R2-R0 0xFF 0xFF CRC
121 Sent when the Start button is pressed for two seconds, i.e. before
122 the start of the race.
124 DI - lap counting direction. 0x00 means counting from 0 upwards,
125 0xFF means counting from preset number of laps downwards.
126 R2-R0 - number of laps. Only lower 4 bits are used, so the count
127 can be obtained as 256*R2 + 16*R1 + R0
130 55 D5 00 FF FF FF FF FF 83
131 55 D5 FF 00 00 04 FF FF CF
136 Format: 0x55 0xD6 F0-F2 N1 N2 B CRC
138 Sent about every 500 ms, current fuel level
140 F0-F2 - encodes the fuel level for each car in 4 bits (values 0-8);
141 car 0 is in higher-order bits of F0 (F0 >> 4), car 5
142 is in lower-order bits of F2 (F2 & 0x0F).
143 N1,N2 - fuel consumption ratio (e.g. 0x14 0x50 means 0.25, 0x00 0x50
144 means the race w/o fuel consumption).
145 B - 0xAA, but the source reports that 0xFF has been rarely seen here as well.
148 55 D6 88 88 88 00 50 AA 3D
149 55 D6 88 18 88 14 50 AA 7F
154 Format: 0x55 0xD7 CT BR 0x83 0x93 0xDB 0xFF CRC
156 CT - the controller which had the back button pressed (0-5)
157 BR - brake level (0x00 - 0 %, 0x02 - 50 %, 0x04 - 100 %)
165 Format: 0x55 0xDB R2-R0 NR 0xFF 0xFF CRC
167 Sent after the start of the qualification.
169 R2-R0 - number of laps. Only lower 4 bits are used, so the count
170 can be obtained as 256*R2 + 16*R1 + R0
171 NR - number of cars participating in the qualification
174 0xDC - end of the race
175 ----------------------
176 Format: 0x55 0xDC 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF CRC
178 Sent twice when the last vehicle crosses the finish line or the race is stopped.
181 55 DC FF FF FF FF FF FF DF
186 Format: 0x55 0xDD 0x00 0xAA 0xAA 0xAA 0xAA 0xAA CRC
188 Sent twice after the reset packet (0xD0) has been sent twice.
191 55 DD 00 AA AA AA AA AA 42
194 0xDE - display change
195 ---------------------
196 Format: 0x55 0xDE WE 0xFF 0xFF 0xFF 0xFF 0xFF CRC
200 Sent in the RES mode: after the SELECT button is pressed for the
201 first time, no packet is sent. The second time the packet with WE = 0
202 is sent, the third time two packets are sent (one weith WE = 0 and
203 one with WE = 1), and the fourth time two packets are sent
204 (one with WE = 1 and one with WE = 0).
212 Format: 0x05 0xEE R0-R5 CRC
214 Sent after the car crosses the finish line and sends back its ID.
216 R0-R5 - one byte for each car. 0xE7 means that this car has crossed the
217 finish line, every other value means it did not cross it:
218 0xAA is sent for unconnected controllers.
219 My pit box with 020 firmware has been seen sending either
220 0xF0 or 0xFE values as well
223 55 EE F0 E7 F0 AA AA AA 3C
224 55 EE FE FE E7 AA AA AA 1E
227 0xFF - controller status
228 ------------------------
229 Format: 0x55 0xFF R0-R5 CRC
231 Sent approximately every 102 ms, or when the change is detected.
233 R0-R5: For each controller there is one byte.
234 0xAA - set when the controller is not connected
235 otherwise, the bits have the following meaning:
238 Bit 5 - lights (0 = on, 1 = off)
239 (note the lights setting is reported for each controller,
240 even though the control unit can set it only for all cars
242 Bit 4 - back button (0 = pressed, 1 = not pressed)
243 Bits 3-0 - throttle (values 0-12 in normal mode, 0-8 in junior mode,
244 and 0-6 in the pit lane)
247 55 FF F0 F0 F0 AA AA AA 7D
248 - controllers 1-3 present and idle, 4-6 not connected