Unique device ID access API. More...

Data Structures
struct	pico_unique_board_id_t
	Unique board identifier. More...

Macros
#define	PICO_UNIQUE_BOARD_ID_INIT_PRIORITY 1000
	Static initialization order.

Functions
void	pico_get_unique_board_id (pico_unique_board_id_t *id_out)
	Get unique ID.
void	pico_get_unique_board_id_string (char *id_out, uint len)
	Get unique ID in string format.

Detailed Description

Unique device ID access API.

RP2040 does not have an on-board unique identifier (all instances of RP2040 silicon are identical and have no persistent state). However, RP2040 boots from serial NOR flash devices which have at least a 64-bit unique ID as a standard feature, and there is a 1:1 association between RP2040 and flash, so this is suitable for use as a unique identifier for an RP2040-based board.

This library injects a call to the flash_get_unique_id function from the hardware_flash library, to run before main, and stores the result in a static location which can safely be accessed at any time via pico_get_unique_id().

This avoids some pitfalls of the hardware_flash API, which requires any flash-resident interrupt routines to be disabled when called into.

Macro Definition Documentation

◆ PICO_UNIQUE_BOARD_ID_INIT_PRIORITY

#define PICO_UNIQUE_BOARD_ID_INIT_PRIORITY 1000

Static initialization order.

This defines the init_priority of the pico_unique_id. By default, it is 1000. The valid range is from 101-65535. Set it to -1 to set the priority to none, thus putting it after 65535. Changing this value will initialize the unique_id earlier or later in the static initialization order. This is most useful for C++ consumers of the pico-sdk.

See https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-constructor-function-attribute and https://gcc.gnu.org/onlinedocs/gcc/C_002b_002b-Attributes.html#index-init_005fpriority-variable-attribute

Here is an example of C++ static initializers that will run before, and then after, pico_unique_id is loaded:

[[gnu::init_priority(500)]] my_class before_instance; [[gnu::init_priority(2000)]] my_class after_instance;

Function Documentation

◆ pico_get_unique_board_id()

void pico_get_unique_board_id ( pico_unique_board_id_t * id_out )

Get unique ID.

Get the unique 64-bit device identifier.

On an RP2040-based board, the unique identifier is retrieved from the external NOR flash device at boot, or for PICO_NO_FLASH builds the unique identifier is set to all 0xEE.

Parameters

id_out a pointer to a pico_unique_board_id_t struct, to which the identifier will be written

◆ pico_get_unique_board_id_string()

void pico_get_unique_board_id_string	(	char *	id_out,
		uint	len )

Get unique ID in string format.

Get the unique 64-bit device identifier formatted as a 0-terminated ASCII hex string.