Serial Output Format

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All serial output formats use the same output packet.

 

Serial Specifications

115,200 bps (software selectable), 8 data, 1 stop, no parity
Packets are sent at 10Hz

 

Packet Description

Words are send with most significant byte first.
The checksum is calculated as the byte sum of the packet subtracted from 0xFF. The byte sum of the packet, including the checksum, should be 0xFF.

 

Byte

Contents

0

Identification byte (0x69)

1

Speed (kph, LSB = 1 kph)

2-3

Rpm (LSB = 0.25 rpm)

4

Gear (0 - 6)

5

ECT (degrees Celsius + 40, LSB 1 deg)

6

IAT (degrees Celsius + 40, LSB 1 deg)

7

Battery voltage (volts, LSB = 0.1V)

8

TPS (0% = 0x15, 100% = 0xE5)

9-10

MAP (mbar, LSB = 1 mbar)

11-12

Injector duration

13

Ignition timing (degs + 0x80, LSB = 0.5 deg)

14

Output bit field

15

Input bit field

16

Unused

17-18

Lambda (0x8000 = 1.00, LSB = 1/0x8000 lambda)

19-20

Knock count (knocks since power on, LSB = 1 knock)

21

Checksum

 

Output bitfield

Bit

Meaning

0

Unused

1

Brake switch

2

AC switch

3

AC clutch

4

Unused

5

EPS/PSP

6

Fuel pump

7

Radiator fan

 

Input bitfield

Bit

Meaning

0

VTEC oil pressure

1

VTEC solenoid #1

2

VTEC solenoid #2

3

MIL

4

Nitrous 1 arm

5

Nitrous 2 arm

6

Nitrous 1 active

7

Nitrous 2 active