ADP1055ACPZ-R7 datasheet(56/140 Pages) AD

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ADP1055

Data Sheet

Rev. A | Page 56 of 140

DOWNLOADING EEPROM SETTINGS TO INTERNAL

REGISTERS

Download User Settings to Registers

The user settings are stored in Page 1 of the EEPROM main

block. These settings are downloaded from the EEPROM into

the registers under the following conditions:



On power-up. The user settings are automatically down-

loaded into the internal registers, powering the ADP1055

up in a state previously saved by the user.



On execution of the RESTORE_USER_ALL command

(Register 0x16). This command allows the user to force a

download of the user settings from Page 1 of the EEPROM

main block into the internal registers.

Download Factory Default Settings to Registers

The factory default settings are stored in Page 0 of the EEPROM

main block. The factory default settings can be downloaded from

the EEPROM into the internal registers using the RESTORE_

DEFAULT_ALL command (Register 0x12).

Note that when this command is executed, the key code and

EEPROM passwords are also reset to their default factory

settings of 0xFFFFFFFF and 0xFF, respectively.

SAVING REGISTER SETTINGS TO THE EEPROM

The register settings cannot be saved to the factory default set-

tings located in Page 0 of the EEPROM main block. This is to

prevent the user from accidentally overriding the factory trim

settings and default register settings.

Save Register Settings to User Settings

The register settings can be saved to the user settings located in

Page 1 of the EEPROM main block using the STORE_USER_ALL

command (Register 0x15). Before this command can be executed,

the EEPROM must first be unlocked for writing (see the Unlock

the EEPROM section).

After the register settings are saved to the user settings, any

subsequent power cycle automatically downloads the latest

stored user information from the EEPROM into the internal

registers.

Note that execution of the STORE_USER_ALL command auto-

matically performs a page erase to Page 1 of the EEPROM main

block, after which the register settings are stored in the EEPROM.

Therefore, it is important to wait at least 35 ms for the operation

to complete before executing the next I2C command.

EEPROM CRC CHECKSUM

As a simple method of checking that the values downloaded from

the EEPROM are consistent with the internal registers, a CRC

checksum is implemented.



When the data from the internal registers is saved to the

EEPROM (Page 1 of the main block), the total number of

1s from all the registers is counted and written into the

EEPROM as the last byte of information. This is called the

CRC checksum.



When the data is downloaded from the EEPROM into the

internal registers, a similar counter that sums all 1s from

the values loaded into the registers is saved. This value is

compared with the CRC checksum from the previous

upload operation.

If the values match, the download operation was successful. If

the values differ, the EEPROM download operation failed, and

the EEPROM CRC fault flag is set (Bit 4 of Register 0x7E).

To read the EEPROM CRC checksum value, execute the

EEPROM_CRC_CHKSUM command (Register 0xD1). This

command returns the CRC checksum accumulated in the

counter during the download operation.

Note that the CRC checksum is an 8-bit cyclical accumulator

that wraps around to 0 when 255 is reached.

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