L9961 datasheet(43/63 Pages) STMICROELECTRONICS

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Figure 15. Timing on the I2C bus

GADG220620221346SA

3.11

Non-volatile memory (NVM)

L9961 allows saving key I2C configuration parameters in the internal NVM. Not all I2C register are stored in the

NVM: refer to the register map file attached, where a color code identifies configuration registers stored in the

NVM.

The following I2C commands allow interacting with the NVM:

•

NVM_WRITE_READ_CODE_CMD = 0xAAAA triggers the NVM upload fetching the data from I2C registers

and moving it to the NVM sectors. The operation lasts TNVM_UPLOAD and during such an interval the MCU

will not be able to perform I2C R/W operations

•

NVM_WRITE_READ_CODE_CMD = 0x5555 triggers the NVM download fetching the data from NVM

sectors and moving it to the I2C registers. The operation lasts TNVM_DOWNLOAD and during such an interval

the MCU will not be able to perform I2C R/W operations.

The NVM can be written a maximum of NNVM_WRITE_CYCLES. If such a limit is exceeded, data retention is not

guaranteed. The NVM_UPLOADS_COUNT counter stores the number of NVM write operation executed and is

saturated to 31.

At each device wakeup the NVM is autonomously re-downloaded and the related I2C configuration registers are

refreshed. Thus, MCU is not required to run configuration functions at each wakeup.

MCU shall disable any load actuation (CHG/DCHG, balancing and FUSE) before launching an NVM download/

upload command.

Data stored in the NVM is checked against corruption:

•

If the trimming and calibration data is corrupted, the CRC_TRIM_CAL_FAIL flag is set and the FAULTN pin

is asserted

•

If the user sectors are corrupted, the CRC_CFG_FAIL flag is set and the FAULTN pin is asserted

Whenever data corruption is detected (CRC_TRIM_CAL_FAIL or CRC_CFG_FAIL), the diagnostic routines will

not be stopped and faults might be inadvertently flagged. However, all the actuations due to internal faults will be

inhibited as if the corresponding masking bit (*_MSK) was set.

A corrupted NVM sector will be downloaded as 0x0.

L9961

Non-volatile memory (NVM)

DS14012 - Rev 1

page 43/63

L9961 Datasheet(PDF) 43 Page - STMicroelectronics