gabbla / osom_firmware

Firmware to be used with speedometer hardware.

Speedometer firmware

Note

It's not possible to debug the project with XC32 v2.10. XC32 v1.43 still works. It seems that there is a missing library.

Packets

Every packet, both received or transmitted, is made as follow:

Pos	Len	Meaning	Value
0	2	Preamble	0x534D
2	2	Message ID
4	1	Payload length
5	1	Command ID
6	n	Payload

Messages

The messages types are enumerated in firmware/src/somparser.h in the enumeration BLECommand.

Not the best name

There are 3 type groups:

• 0x00 to 0x0F are commands reserved for the master only, managed by BLEApp;
• 0x10 to 0x4F are generic commands to control the system;
• 0x50 to 0x?? are response messages sent by the system to the received commands;
• 0xF0 to 0xFF are special meaning messages sent by the system

There are also some common definitions along all the exchanged messages:

Channel selection

Value	Channel
0	none
1	right
2	left
3	both
4-F	reserved

TODO ACK

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0x00 to 0x0F

0x00 Ping

• Payload length 0

Simply check if the system is up and running. TODO response

TODO other commands

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0x10 to 0x4F

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0x10 Mode setting

• Payload length 1

Payload data:

Field	Bit	Meaning
Mode	7-4	Mode selection
Channel	3-0	Channel as described above

Mode

Value	Mode	Channel
0	Free Start	Single
1	KO System	Dual
2	Given Start	Single
3-F	Reserved	-

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0x11 Start positioning

This command place the system in the so-called positioning mode.

• Payload length: 1

Payload data

Field	Bit	Meaning
Reserved	7-4	-
Channel to be used	3-0	Channel as described above

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0x12 Stop positioning

This command exits the so-called positioning mode.

• Payload length: 0

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0x50 to 0x??

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0x51 Channel positioning status

This message notify the user about the channel status change.

• Payload length: 1

Payload data

Field	Bit	Meaning
Channel	7-4	Channel as described above
Status	0	Channel status

Channel status

Value	Meaning
0	The channel receiver is covered, check positioning
1	The channel receiver is receiving the laser

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