Serial to CAN Bridge

Send and receive CAN frames over a serial connection.

Commands

Commands are encoded with MessagePack.

PC -> MCU

1. Command: uint
2. followed by an argument

Commands	Argument	Explanation
0x00	MessagePack CAN frame	send CAN frame
0x01	CAN ID filter list	selectively receive CAN frames

MCU -> PC

The MCU just forwards every CAN frame it receives encoded as described below.

Message Pack CAN Frame

A CAN frame is encoded as a MessagePack array with following entries:

Order	Type	Explanation

1. | bool | IDE extended frame id flag
2. | bool | RTR remote transmission request flag
3. | uint | CAN ID (11bit or 29bit)
4. | uint | DLC data length code, values: 0 - 8
5. | bin | CAN frame data, length: 0 - 8 bytes

Message Pack CAN ID Filter List

The filter list is a MessagePack array of at least one filter entry. One filter entry is composed of an ID with a corresponding mask and is encoded as a MessagePack array as following:

Order	Type	Explanation

1. | bool | IDE extended frame id flag
2. | bool | RTR remote transmission request flag
3. | uint | CAN ID (11bit or 29bit)
4. | bool | mask: IDE
5. | bool | mask: RTR
6. | uint | mask: ID

A mask bit set to 1 (or true) means the corresponding field has to match the given ID, 0 (or false) means the field doesn't matter. For a CAN frame to pass the filter it has to match at least one filter entry.