Bridges Python application serial communication with the CAN bus. More...

#include <LccNodeSlcanSerialBridge.h>

Inherits Executable.

Collaboration diagram for LccNodeSlcanSerialBridge< SerialType >:

Classes
class	WritePort
	State machine running in the OpenMRN cooperative executor, registered to receive data that needs to be sent to the port. More...

Public Member Functions
	LccNodeSlcanSerialBridge (SerialType port, CanHubFlow pCanHub)
	Constructor. More...

	~LccNodeSlcanSerialBridge ()
	Destructor.

void	run ()
	Called by the loop to check for possible serial or GridConnect packets to be read and processed. More...

Private Member Functions
void	_loop_for_read ()

uint8_t	_encodeCanFrameToGcPacket (const can_frame *pCanFrame, unsigned char buf[])
	Encode a CAN frame (struct) to a GridConnect packet in the following format: ':' (0x3A) start of packet 'X' (0x58) extended id (4 bytes) ID converted from 4-bytes to 8 byte ascii 'R' (0x52) remote indicator data bytes converted to 2-byte ascii ';' (0x3F) end of packet. More...

char	nibble_to_ascii (const uint8_t nibble)
	Converts a nibble to its ASCII character representation. More...

String	_readSlcanFrameFromSerial ()
	Read a CAN frame from the serial port. More...

bool	_decodeSlcanFrameToCanFrame (const String pSlcanFrame, can_frame pCanFrame)
	Deocode a Slcan frame to CAN frame: More...

void	_loop_for_write ()

bool	_decodeGcPacketToCanFrame (can_frame *pCanFrame)
	Decodes a GridConnect packet in to a CAN frame (struc) Supports multiple frames of data within a packet, but only processes one frame of data per invocation (uses writeOfs_ to keep position within the packet) More...

String	_encodeCanFrameAsSlcanFrame (const can_frame *pCanFrame)
	Encodes a CAN frame into a Slcan Frame. More...

void	_printHex (const uint8_t *data, const uint8_t length)
	Print data in hexadecimal form for debugging. More...

Private Attributes
SerialType *	pPort_
	Serial port object.

Service *	pService_
	Access to the stack's executor.

HubFlow	txtHub_ { pService_ }
	Hub for the textual data.

Buffer< HubData > *	pWriteBuffer_ { nullptr }
	Buffer for outgoing data.

WritePort	writePort_ { this, pService_ }
	State flow with queues for output frames generated by the stack.

size_t	writeOfs_
	Offset into GC packet of data being processed (in case there is more than one frame within the packet)

Detailed Description

template<class SerialType>
class LccNodeSlcanSerialBridge< SerialType >

Bridges Python application serial communication with the CAN bus.

This class handles bridging between OpenMRN GridConnect packet format and the expected CAN frame format over used by Python CAN-libary with serial communication.

Definition at line 69 of file LccNodeSlcanSerialBridge.h.

Constructor & Destructor Documentation

◆ LccNodeSlcanSerialBridge()

template<class SerialType >

LccNodeSlcanSerialBridge< SerialType >::LccNodeSlcanSerialBridge	(	SerialType *	port,
		CanHubFlow *	pCanHub
	)

inline

Constructor.

Parameters

port	Serial port object (HardwareSerial, SoftwareSerial, or BluetoothSerial).
pCanHub	Core CAN frame router of the OpenMRN stack, usually from stack()->pCanHub().

Format of the CAN Frame over Serial is defined here: https://python-can.readthedocs.io/en/stable/interfaces/serial.html 0xAA start of frame, 4-byte timestamp, DLC byte, Arbitration ID - 4 byte, Payload, 0xBB end of frame.

Definition at line 80 of file LccNodeSlcanSerialBridge.h.

Member Function Documentation

◆ _decodeGcPacketToCanFrame()

template<class SerialType >

bool LccNodeSlcanSerialBridge< SerialType >::_decodeGcPacketToCanFrame ( can_frame * pCanFrame )

inlineprivate

Decodes a GridConnect packet in to a CAN frame (struc) Supports multiple frames of data within a packet, but only processes one frame of data per invocation (uses writeOfs_ to keep position within the packet)

Parameters

pCanFrame hold the decode GC packet's frame

Returns: True if a CAN frame was decode from the GC packet's data, otherwise false.

< Get start of a packet's CAN frame

< Check next character

< udpate offset as packet is processed

< Packet found?

< return whether or not CAN data was found and converted

Definition at line 322 of file LccNodeSlcanSerialBridge.h.

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◆ _decodeSlcanFrameToCanFrame()

template<class SerialType >

bool LccNodeSlcanSerialBridge< SerialType >::_decodeSlcanFrameToCanFrame	(	const String *	pSlcanFrame,
		can_frame *	pCanFrame
	)

inlineprivate

Deocode a Slcan frame to CAN frame:

Parameters

pSlcanFrame string holding slcan frame to be decoded.

Slcan frame start with either a 't' (standard id) or 'T' (extended ID); followed by the ID, DLC byte, and data.

Parameters

pCanFrame holds the decode CAN frame

Returns: True if slcan was decoded

Definition at line 271 of file LccNodeSlcanSerialBridge.h.

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◆ _encodeCanFrameAsSlcanFrame()

template<class SerialType >

String LccNodeSlcanSerialBridge< SerialType >::_encodeCanFrameAsSlcanFrame ( const can_frame * pCanFrame )

inlineprivate

Encodes a CAN frame into a Slcan Frame.

Parameters

pCanFrame to hold the encoded Slcan frame

Returns: True if a Slcan frame was encode succesffuly, otherwise false.

Definition at line 344 of file LccNodeSlcanSerialBridge.h.

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◆ _encodeCanFrameToGcPacket()

template<class SerialType >

uint8_t LccNodeSlcanSerialBridge< SerialType >::_encodeCanFrameToGcPacket	(	const can_frame *	pCanFrame,
		unsigned char	buf[]
	)

inlineprivate

Encode a CAN frame (struct) to a GridConnect packet in the following format: ':' (0x3A) start of packet 'X' (0x58) extended id (4 bytes) ID converted from 4-bytes to 8 byte ascii 'R' (0x52) remote indicator data bytes converted to 2-byte ascii ';' (0x3F) end of packet.

Parameters

pCanFrame	CAN pCanFrame to encode.
buf	Buffer to store the encoded packet.

Returns: Length of the encoded packet.

Definition at line 203 of file LccNodeSlcanSerialBridge.h.

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◆ _loop_for_read()

template<class SerialType >

void LccNodeSlcanSerialBridge< SerialType >::_loop_for_read ( )

inlineprivate

Handles Slcan frame coming from serial port and going out to the OpenMRN Grid Connect Hub. Process Slcan frames from serial by:

converting Slcan frame to CAN frame
encode CAN frame to GC packet
queuing the GC packet with GridConnect Hub

< Allocate a buffer to build the GridConnect frame and data in

< yes, adjust the buffer to the actual size of the packet

Definition at line 157 of file LccNodeSlcanSerialBridge.h.

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◆ _loop_for_write()

template<class SerialType >

void LccNodeSlcanSerialBridge< SerialType >::_loop_for_write ( )

inlineprivate

Handles processing OpenMRN GridConnect packet and sending Slcan frame towards the serial port. Process GC packets to Slcan frames and out to serial by:

Get a single CAN frame from the GC packet
Convert the GC (ascii data) to CAN frame
Write CAN frame to the serial port
Update offset into processing of the GC packet
If done with packet, notify that we're ready for another packet, otherwise continue processing on next invocation of this code.

< Clear the buffer after writing

< Wake up state flow to release buffer and take next from the queue

Definition at line 299 of file LccNodeSlcanSerialBridge.h.

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