EEPROM in microcontrollers AVR Atmega

EEPROM, Atmega

Microcontrollers AVR Atmega48 / 88/168/328 contain the EEPROM memory of 256/512/512 / 1K bytes , respectively. EEPROM in AVR microcontrollers can support up to 100,000 write cycles. Access to non-volatile memory is carried out through three types of registers:

  • EEARH, EEARL - registers the addressing of memory cells. In case Atmega48 EEARH absent, because in this type of microcontroller 256 is present in all memory cells. EEARH responsible for the high byte of memory address, EEARL for the least significant byte;
  • EEDR - register for writing and reading data;
  • EECR - register control, this register is setting the actions to be performed with the memory.

A detailed description of EEPROM registers

EEARH and EEARL - registers EEPROM cell address

Bits from 9 to 15 are reserved and always read with the value zero.

Bits from 0 to 8 are used to indicate non EEPROM memory cell to which the treatment will be.

EEDR - EEPROM data register

Bits from 2 to 7 - which is written bits in the information to be recorded in EEPROM or read from it.

Bits from 6 to 7 - bits are reserved

Bits from 4 to 5 - EEPM1 and EEPM0 - EEPROM used to set the operation mode.

  • EEPM1 = 0, EEPM0 = 0 - An atomic operation is the removal and recording of data (duration 3.4 ms)
  • EEPM1 = 0, EEPM0 = 1 - Only the deletion of data (duration 1.8 ms)
  • EEPM1 = 1, EEPM0 = 0 - Data Entry Only (duration 1.8 ms)
  • EEPM1 = 1, EEPM0 = 1 - Reserved for future use

Bit 3 - EERIE - this bit is used to enable interrupts, in case if you are allowed to interrupt the firmware of your controller.

Bit 2 - EEMPE - protection bit of the recording. Delays process of writing data to the EEPROM on the four cycles to EEPROM had time to prepare for the recording of data.

Bit 1 - EEPE - write bit start, exhibited to start recording, cleared to zero in hardware, at a time when the recording is completed. Therefore, it may be used to control the data recording process in EEPROM.

Bit 0 - WERE - bit start reading. exhibit for reading from EEPROM launch.

Read and write operations

Atmega EEPROM in a very slow interface, which requires up to 4 ms to perform write operations. Therefore it is very important to check that the previous write operation is completed successfully.

;======= EEPROM write procedure in ======================================================
 EEWrite: 
    sbic EECR,EEPE          ; We expect that over the previous write operation.
    rjmp EEWrite            ; Out of the loop as long as the flag is cleared EEPE
    cli                     ; Then we put out a ban on interrupting.
    out EEARL,r16           ; Set the address of the cell to which we refer
    out EEDR,r17            ; as well as write data to the register information,
                            ; that will keep
    sbi EECR,EEMPE          ; set protection on record
    sbi EECR,EEPE           ; set the write flag
    sei                     ; then allow interrupt
    ret                     ; and return from the subroutine.
 ;======= The procedure of reading from the EEPROM ======================================
 EERead: 
    sbic EECR,EEPE          ; We expect that over the previous write operation. 
    rjmp EERead 
    out  EEARL, r16         ; Set the address of the cell to which we refer
    sbi  EECR,EERE          ; Start reading setting for reading the flag
    in   r17, EEDR          ; Return the reading result in the desired register
    ret 
 ;=======================================================================================

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TT
June 13, 2019, 7:01 p.m.
Taimoor Tanweer

C++ - Test 001. The first program and data types

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TT
June 13, 2019, 6:51 p.m.
Taimoor Tanweer

C++ - Test 002. Constants

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ВМ
June 13, 2019, 12:30 p.m.
Ваня Мороз

C++ - Test 001. The first program and data types

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Last comments
i
June 17, 2019, 6:10 a.m.
ingenfly

Только по осям xAxis2, уAxis2 значения начинаются с 0. Почему-то xAxis2 и xAxis не синхронизированы по данным. Ну и QCustomPlot последний.
June 16, 2019, 8:21 p.m.
Евгений Легоцкой

Добрый день. Ну точно также добавляете ту же самую информацию на ось xAxis2, только добавляете другое форматирование customPlot->xAxis2->setDateTimeFormat("hh:mm"); если я ...
EF
June 14, 2019, 1:56 p.m.
Egor Fomin

Спасибо за ваш ответ, у меня получилось реализовать это. Тем не менее появилась другая проблема, поэтому опять надеюсь на вашу помощь. Скажем, я уже выставил точки и они соеденены. Когда я нач...
d
June 13, 2019, 2:47 p.m.
damix

Можно классу, который описывает точку, добавить сигнал, который подавать (emit), когда точка перемещается (переопределить mouseMoveEvent или mouseReleaseEvent). Так вот эти сигналы у каждой из...
i
June 13, 2019, 2:09 p.m.
ingenfly

Здравствайте! Подскажите, пожалуйста: customPlot->xAxis2->setTickLabels(true); //Здесь включается отображение данных на оси xAxis2. а можно как-то продублировать информацию cus...
Now discuss on the forum
I
June 19, 2019, 1:41 p.m.
Intruder

Всем добрый день. При разборе XML файла наткнулся на тег вот такого плана: <TagName attribute1="value1" attribute2="value2" /> При попытке проверить на наличие такого элеме...
June 19, 2019, 12:55 p.m.
Михаиллл

Скажите пожалуйста, как его в таком случае перемещать и удалять?
June 18, 2019, 7:50 p.m.
Дмитрий

Большое спасибо! SDK заработал.К сожалению удалось продвинутся только на один шаг. При сборке чистого проекта NDK выдаёт следующие ошибки C:\Android\ndk-bundle/toolchains/arm-linux-andr...
June 18, 2019, 4:59 p.m.
Михаиллл

Добрый день.В этом учебнике представлен код INSTALLED_APPS = ( ... 'rest_framework', 'snippets.apps.SnippetsConfig',) На строчке 'snippets.apps.SnippetsConf...
June 18, 2019, 2:24 p.m.
Михаиллл

Спасибо, работает.Послушаю вашего совета.
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