Collaboration diagram for u-blox GPS Device communication:

Modules
	UBX Commands

	UBX Message handling

Files
file	GPSCommands.h

file	GPSMessages.h

file	GPSSerial.h

file	GPSTypes.h

Classes
struct	ubx_message
	Internal representation of a UBX message. More...

struct	ubx_message_name
	UBX Message descriptions. More...

struct	ubx_nav_pvt
	Represent decoded NAV-PVT message. More...

Macros
#define	UBX_SERIAL_BUFF 4096
	Serial buffer size.

#define	UBX_SYNC_BYTE1 0xB5
	UBX Serial synchronisation byte 1. More...

#define	UBX_SYNC_BYTE2 0x62
	UBX Serial synchronisation byte 2. More...

Typedefs
typedef enum ubx_class	ubx_class
	UBX Message class ID bytes.

typedef struct ubx_message	ubx_message
	Internal representation of a UBX message. More...

typedef struct ubx_message_name	ubx_message_name
	UBX Message descriptions.

typedef struct ubx_nav_pvt	ubx_nav_pvt
	Represent decoded NAV-PVT message.

Enumerations
enum	ubx_class { UBXNAV = 0x01 , UBXRXM = 0x02 , UBXINF = 0x04 , UBXACK = 0x05 , UBXCFG = 0x06 , UBXUPD = 0x09 , UBXMON = 0x0A , UBXAID = 0x0B , UBXTIM = 0x0D , UBXESF = 0x10 , UBXMGA = 0x13 , UBXLOG = 0x21 , UBXSEC = 0x27 , UBXHNR = 0x28 }
	UBX Message class ID bytes.

Functions
int	ubx_openConnection (const char *port, const int initialBaud)
	Set up a connection to a UBlox module on a given port. More...

void	ubx_closeConnection (int handle)
	Close a connection opened with ubx_openConnection() More...

bool	ubx_readMessage (int handle, ubx_message *out)
	Static wrapper around ubx_readMessage_buf() More...

bool	ubx_readMessage_buf (int handle, ubx_message out, uint8_t buf[UBX_SERIAL_BUFF], int index, int *hw)
	Read data from handle, and parse message if able. More...

bool	ubx_waitForMessage (const int handle, const uint8_t msgClass, const uint8_t msgID, const int maxDelay, ubx_message *out)
	Read (and discard) messages until required message seen or timeout reached. More...

bool	ubx_writeMessage (int handle, const ubx_message *out)
	Send message to attached device. More...

Detailed Description

Macro Definition Documentation

◆ UBX_SYNC_BYTE1

#define UBX_SYNC_BYTE1 0xB5

UBX Serial synchronisation byte 1.

0xB5 as defined in UBlox documentation.

Represents the UTF-8 µ glyph

Definition at line 43 of file GPSTypes.h.

◆ UBX_SYNC_BYTE2

#define UBX_SYNC_BYTE2 0x62

UBX Serial synchronisation byte 2.

Defined as 0x62 in UBlox documentation. Represents a b in ASCII or UTF-8.

Definition at line 50 of file GPSTypes.h.

Typedef Documentation

◆ ubx_message

typedef struct ubx_message ubx_message

Internal representation of a UBX message.

All messages must start with two sync bytes: 0xB5 0x62

Short messages are stored in the data array, larger messages will be stored at the location pointed to by the extdata member.

If extdata is set, it must be explicitly freed when message is disposed of.

Function Documentation

◆ ubx_closeConnection()

void ubx_closeConnection ( int handle )

Close a connection opened with ubx_openConnection()

Currently just closes the handle, but could deconfigure and reset the module or put it into a power saving mode in future.

Parameters

[in] handle File descriptor from ubx_openConnection()

Definition at line 111 of file GPSSerial.c.

◆ ubx_openConnection()

int ubx_openConnection	(	const char *	port,
		const int	initialBaud
	)

Set up a connection to a UBlox module on a given port.

Uses openSerialConnection() from the base library to open an initial connection, then sends UBX commands to configure the module for 115200 baud UBX output.

If the module was already operating at 115200 then it will stop listening to serial commands when we transmit at the wrong rate, so this function will sleep for 1 second before configuring the protocols again.

Parameters

[in]	port	Path to character device connected to UBlox module
[in]	initialBaud	Initial baud rate for connection. Usually 9600, but may vary.

Returns: File descriptor for use with other commands

Definition at line 51 of file GPSSerial.c.

◆ ubx_readMessage()

bool ubx_readMessage	(	int	handle,
		ubx_message *	out
	)

Static wrapper around ubx_readMessage_buf()

For single threaded development and testing, uses static variables rather than requiring state to be tracked by caller.

See ubx_readMessage_buf() for full description.

Parameters

[in]	handle	File descriptor from ubx_openConnection()
[out]	out	Pointer to message structure to fill with data

Returns: True if out now contains a valid message, false otherwise.

Definition at line 125 of file GPSSerial.c.

◆ ubx_readMessage_buf()

bool ubx_readMessage_buf	(	int	handle,
		ubx_message *	out,
		uint8_t	buf[UBX_SERIAL_BUFF],
		int *	index,
		int *	hw
	)

Read data from handle, and parse message if able.

Pulls data from handle and stores it in buf, tracking the current search position in index and the current fill level/buffer high water mark in hw

The source handle can be anything supported by read(), but would usually be a file or a serial port.

If a valid message is found then it is written to the structure provided as a parameter and the function returns true.

If a message cannot be read, the function returns false and the sync1 field is set to an error value:

0xFF means no message found yet, and more data is required
0xFD is a synonym for 0xFF, but indicates that zero bytes were read from source. This could indicate EOF if reading from file, but can be ignored when streaming from a device.
0xAA means that an error occurred reading in data
0XEE means a valid message header was found, but no valid message

Parameters

[in]	handle	File descriptor from ubx_openConnection()
[out]	out	Pointer to message structure to fill with data
[in,out]	buf	Serial data buffer
[in,out]	index	Current search position within `buf`
[in,out]	hw	End of current valid data in `buf`

Returns: True if out now contains a valid message, false otherwise.

Definition at line 158 of file GPSSerial.c.

◆ ubx_waitForMessage()

bool ubx_waitForMessage	(	const int	handle,
		const uint8_t	msgClass,
		const uint8_t	msgID,
		const int	maxDelay,
		ubx_message *	out
	)

Read (and discard) messages until required message seen or timeout reached.

Messages are read with ubx_readMessage() and discarded until either a message matches the supplied message class and ID values or the maximum delay time is reached.

Note that the function exits as soon as the time specified by maxDelay is exceeded. The maximum delay specified in this function is 50us, but no guarantees are given regarding time spent reading in messages.

Parameters

[in]	handle	File descriptor from ubx_openConnection()
[in]	msgClass	Message class to wait for
[in]	msgID	Message ID/Type to wait for
[in]	maxDelay	Timeout in seconds.
[out]	out	Pointer to message structure to fill with data

Returns: True if required message found, false otherwise (timeout reached)

Definition at line 276 of file GPSSerial.c.

◆ ubx_writeMessage()

bool ubx_writeMessage	(	int	handle,
		const ubx_message *	out
	)

Send message to attached device.

Takes a ubx_message, validates the checksum and sync bytes and writes data to the device or file connected to handle.

Parameters

[in]	handle	File descriptor from ubx_openConnection()
[in]	out	Pointer to message structure to be sent.

Returns: True if data successfullt written to handle

Definition at line 298 of file GPSSerial.c.

Modules

Files

Classes

Macros

Typedefs

Enumerations

Functions

Detailed Description

Macro Definition Documentation

◆ UBX_SYNC_BYTE1

◆ UBX_SYNC_BYTE2

Typedef Documentation

◆ ubx_message

Function Documentation

◆ ubx_closeConnection()

◆ ubx_openConnection()

◆ ubx_readMessage()

◆ ubx_readMessage_buf()

◆ ubx_waitForMessage()

◆ ubx_writeMessage()