OTP

One-time programmable slots holding factory data. More...

Enumerations
enum	OtpWriteResult { OtpWriteSuccess = 0 , OtpWriteFailAlreadyWritten = 1 , OtpWriteFailCorrupt = 2 }
	Result of otp_write_slot(). More...

Functions
uint8_t *	otp_get_lock (const uint8_t index)
	Get the lock byte of a slot.
bool	otp_is_locked (const uint8_t index)
	Check whether the OTP storage is locked.
char *	otp_get_slot (const uint8_t index)
	Read a slot.
OtpWriteResult	otp_write_slot (const uint8_t index, const char *value)
	Write a string to an unwritten slot.

Detailed Description

One-time programmable slots holding factory data.

Each slot holds a NUL-terminated string of up to 31 characters, stored in a flash security register. A slot can be written once.

char *serial = otp_get_slot(OTP_SERIAL);

Enumeration Type Documentation

OtpWriteResult

enum OtpWriteResult

Result of otp_write_slot().

Enumerator
OtpWriteSuccess	Slot written and verified.
OtpWriteFailAlreadyWritten	Slot already holds data.
OtpWriteFailCorrupt	Invalid slot or value, or the write could not be verified.

Function Documentation

otp_get_lock()

uint8_t * otp_get_lock

(

const uint8_t

index

)

Get the lock byte of a slot.

Parameters

index

Slot index.

Returns

Lock byte, or NULL when slots have no individual lock.

otp_get_slot()

char * otp_get_slot

(

const uint8_t

index

)

Read a slot.

Parameters

index

Slot index.

Returns

Slot contents, in a static buffer overwritten by the next read, or NULL on error. An unwritten slot reads as 0xFF bytes.

otp_is_locked()

bool otp_is_locked

(

const uint8_t

index

)

Check whether the OTP storage is locked.

Locking applies to the whole security register holding the slots.

Parameters

index

Slot index.

Returns

true if locked.

otp_write_slot()

OtpWriteResult otp_write_slot	(	const uint8_t	index,
		const char *	value
	)

Write a string to an unwritten slot.

Parameters

index	Slot index.
value	NUL-terminated string, at most 31 characters.

Returns

Write result.