ADM1266ACPZ-R7 datasheet(26/62 Pages) AD

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ADM1266

Data Sheet

Rev. A | Page 26 of 62

MEMORY

OVERVIEW

The ADM1266 contains internal EEPROM (nonvolatile memory)

to store the mini boot loader, the boot loader, firmware, config-

uration settings, and fault log information. The mini boot loader,

boot loader, firmware, and configuration settings each have a

main copy and a backup copy in the memory. Each section has

its own unique cyclic redundancy check (CRC), and each black

box record has its own unique CRC.

POWER-UP

At power-up, the main mini boot loader checks the data of the

main boot loader and compares it to the CRC. If the data is

corrupted, the main mini boot loader checks the data of the

backup bootloader and compares it with its CRC. If the backup

bootloader data matches the CRC, this data is copied to the

main boot loader and is fixed (the ADM1266 copies the data

from backup memory to main memory and corrects the

corrupted data). Then, the main boot loader starts to execute

the boot loader. The main boot loader checks the data of the

main firmware and compares it to the CRC. If the data is

corrupted, the main boot loader checks the data of the backup

firmware and compares this data to the CRC. If the backup

firmware data matches the CRC, the ADM1266 copies it over to

the main firmware and fixes the data. Then, the ADM1266

starts to execute the firmware. The firmware then checks the

data of the main and backup configuration and compares it with

the respective CRCs. If both sections match the calculated CRC

value of memory with the saved CRC value, then the ADM1266

runs the main configuration. If one of the sections matches the

CRC, the ADM1266 runs the correct configuration. In a multi-

device system, all the devices share the information about their

main and backup configuration with the master device. Then, the

master device makes a decision and communicates to all the

devices which section of the configuration memory to run.

If at any given point for any of the sections both the main and

backup sections are corrupted, the device does not proceed.

MANUAL CRC CALCULATIONS

The ADM1266 has several commands to validate the condition

of the memory. Use MEMORY_RECALCULATE_CRC

(Register 0xF9) to trigger the device to recalculate the CRC

of all the sections and to report the status in STATUS_MFR_

SPECIFIC_2 (Register 0xED). The time required to recalculate

the CRC of all the sections is approximately 500 ms.

REFRESH

The ADM1266 allows data to be copied from the main sections

to the backup sections, and vice versa. REFRESH_FLASH

(Register 0xF5) can be used to trigger this function. When this

function is triggered, the ADM1266 checks the CRC of both the

main and backup sections and copies data from the expected

data (not corrupted) section over to the corrupted section, and

vice versa. Based on the data written to REFRESH_FLASH, the

user can choose to refresh certain sections of the memory. To

increase the reliability of the memory, it is recommended to run

this refresh feature once every 30 days.

When the refresh feature is running, it takes 32 ms to refresh

each page. During this time, all faults are latched but not processed.

After refreshing each page, if there is any sequence event, the

refreshing is temporarily aborted and the sequencing and fault

handling functions are executed. At the end of this process, the

ADM1266 resumes the refreshing function. It takes approximately

9 sec to finish refreshing all the sections of the ADM1266.

PMBus write operations are not allowed when the refresh feature is

running. PMBus read operations are clock stretched and

processed at the end of refreshing each page.

AUTO REFRESH

The ADM1266 can be configured to run the refresh feature

automatically after this feature is enabled and saved to the memory.

After one day, each time the device is powered up the device

automatically starts the refresh of the boot loader, firmware, and

configuration sections. Once a day, the device runs the CRC

check. If any of the mini boot loader, boot loader, firmware, or

configuration sections are corrupted, the device automatically

starts the refresh of the mini boot loader, the boot loader, firmware,

and the configuration sections. After the initial refresh that

occurs after one day, the ADM1266 can be preprogrammed to

automatically start refresh every N days, where N varies from

1 day to 255 days. The default setting is 30 days.

ACCELERATION FACTOR

The ADM1266 contains internal EEPROM (nonvolatile memory)

to store the mini boot loader, the boot loader, the firmware,

configuration settings, and fault log information. EEPROM

endurance and retention are specified over the operating junction

temperature range (see the Absolute Maximum Ratings section

and the Electrical Specifications section).

ADM1266ACPZ-R7 数据表(PDF) 26 Page - Analog Devices

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