btnut/btnode/include/eepromdb/btn-eepromdb.h File Reference

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Detailed Description

Provides support for storing and retrieving 'features' of the particular BTnode the software is running. This can be used to store, how much memory is availabe, or what the user readable name of this device is. Or what sensors are connected to it.

Author:

Martin Hinz <btnode@hinz.ch>

Features are addressed using a four byte identifier 'xxxx'. For string features, the last byte has to be '=', so all string feature id look like 'xxx=' followed by the string in the eeprom.

The feature data is stored in the EEPROM of the device. The first implementation supports Int32 and strings (len <= 16) feature data.

To create such a feature ID, you can use the macro FOURCC(a,b,c,d) that takes four characters and creates a 4 char constant. The simple use of 'abcd' is deprecated.

#include <io.h>

Defines
#define	BTN_EEPROMDB_ID_SIZE   4
#define	BTN_EEPROMDB_INT_SIZE   4
#define	BTN_EEPROMDB_STRING_SIZE   16
#define	FOURCC(a, b, c, d)   ( (u_long) a << 24 | (u_long) b << 16 | (u_long) c << 8 | (u_long) d )
	Create a 32 constant from 4 single characters.
Functions
u_char	btn_eepromdb_delete (u_long id)
	Delete a value in the eeprom database in the EEPROM of the BTnode.
u_short	btn_eepromdb_get (u_long id, u_short size, void *data)
	Get a value in the eeprom database in the EEPROM of the BTnode.
u_long	btn_eepromdb_get_by_index (u_short index)
	Get the value id of value nr index. This is used to enumerate the eeprom database.
u_short	btn_eepromdb_store (u_long id, u_short size, void *data)
	Stores into the eepromdb on the EEPROM of the BTnode.

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Define Documentation

#define FOURCC	(	a,
		b,
		c,
		d		)	( (u_long) a << 24 | (u_long) b << 16 | (u_long) c << 8 | (u_long) d )

Create a 32 constant from 4 single characters.

Parameters:

a,b,c,d

id characters

Returns:

32 bit integer constant

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Function Documentation

u_char btn_eepromdb_delete

(

u_long

id

)

Delete a value in the eeprom database in the EEPROM of the BTnode.

Parameters:

id

32 bit value id. String features have to be 'xxx='"

Returns:

1 ok or 0 to indicate an error.

u_short btn_eepromdb_get	(	u_long	id,
		u_short	size,
		void *	data
	)

Get a value in the eeprom database in the EEPROM of the BTnode.

Parameters:

	id	32 bit value id. String value have to be 'xxx='"
	size	Max size of the data buffer. Only used for strings.
	data	Pointer the data buffer

Returns:

Size of the data retrieved (strlen in case of string) or 0 to indicate an error.

Note:

: To retrieve a string with len=16, a buffer of size=17 is needed as the terminating '' is always added.

u_long btn_eepromdb_get_by_index

(

u_short

index

)

Get the value id of value nr index. This is used to enumerate the eeprom database.

Parameters:

index

Index of value id to get

Returns:

Value ID or 0 for last value

u_short btn_eepromdb_store	(	u_long	id,
		u_short	size,
		void *	data
	)

Stores into the eepromdb on the EEPROM of the BTnode.

Parameters:

	id	32 bit Feature id. String id have to be 'xxx='"
	size	Size of the data to store. (Only relevant with string values, maximal BTN_EEPROMDB_STRING_SIZE bytes
	data	Pointer the data to be stored (string or pointer of long)

Returns:

Size of the data successfully stored or 0 to indicate an error.

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