EEPROM read and write examples

Almost all AVR microcontrollers are equipped with Flash ROM, SRAM, and EEPROM memories. Flash ROM is a program memory that is not afraid of power failure; SRAM is a static data memory that loses data after power failure; EEPROM is an electrically erasable memory that is not afraid of power failure and is generally used to store data that needs to be modified frequently.

    There are generally two ways to erase and write EEPROM. One is to erase and write the EEPROM with the microcontroller's own program when the microcontroller is running normally, and the other is to use a programmer to erase and write the EEPROM independently.

1: The following is an example of erasing the EEPROM by the microcontroller's own program when the microcontroller is running normally: '

EEPROM reading and writing examples'www.avrdiy.com 'BASCOM-AVR1.11.8.1 'Program function, Press the INT0 button, then the PC5 port will output a 0.5Hz square wave, ' Press the INT0 button again, then the PC5 port will output a 0.2Hz square wave, ' The output frequency of PC5 after restarting is the same as before restarting '------------------------------------------------------------------------------- $regfile = "m88def.dat" $crystal = 1000000 Config Int0 = Falling 'Define falling edge to trigger INT0 interrupt Ddrd.2 = 0 Portd.2 = 1 Enable Interrupts 'Turn on global interrupt Enable Int0 'Turn on INT0 interrupt On Int0 Int0_ok 'Interrupt INT0 entry '------------------------------------------------------------------------------- 'Define variable A as byte type and store it in EEPROM. The storage location is automatically arranged by the compiler. 'The main program does not assign a value to A, so the data of A may be 255 when it is run for the first time. Dim A As Eram Byte Dim B As Byte '------------------------------------------------------------------------------- Ddrc.5 = 1 Portc.5 = 0 B = A Do     Waitms B     Portc.5 = Not Portc.5 'Invert operation Loop End '------------------------------------------------------------------------------- Int0_ok:     If A = 100 Then         A = 250         Else         A = 100     End If     B = A Return The above program can also be rewritten as follows: 'EEPROM reading and writing example'www.avrdiy.com ' BASCOM-AVR1.11.8.1 $regfile = "m88def.dat" $crystal = 1000000 Config Int0 = Falling 'Define falling edge to trigger INT0 interrupt Ddrd.2 = 0 Portd.2 = 1 Enable Interrupts 'Turn on global interrupt Enable Int0 'Turn on INT0 interrupt On Int0 Int0_ok 'Interrupt INT0 entry '------------------------------------------------------------------------------ Dim A As Byte '------------------------------------------------------------------------------- Ddrc.5 = 1 Portc.5 = 0 Readeeprom A,2 'Read the value of EEPROM address 2 and assign it to A Do     Waitms A     Portc.5 = Not Portc.5 'Invert operation Loop End '------------------------------------------------------------------------------- Int0_ok:     If A = 100 Then         A = 250         Else         A = 100     End If     Writeeeprom A,2 'Save the value of A in address 2 of EEPROM Return








































































2: When using the programmer to perform independent write operations on the EEPROM, you must first have an EEP file ready to be written. BASCOM-AVR can generate such a file. The program is as follows:

'EEPROM reading and writing examples
' www.avrdiy.com
'BASCOM-AVR1.11.8.1
$regfile = "m8515.dat"
$crystal = 1000000
Config Lcdpin = Pin , Db4 = Portb.4 , Db5 = Portb.5 , Db6 = Portb.6 , Db7 = Portb.7 , E = Portb.2 , Rs = Portb.3
Config Lcd = 16 * 2
Dim A(9) As Byte
Dim I As Byte

Cls
Waitms 100
For I = 3 To 7
    Readeeprom A(i) , I 'Read data from address I of the EEPROM and assign it to array A(I)
    Lcd A(i) ; "|";
Next I
End

$eeprom 'Tell the compiler that the data in array Shuzu will be stored in EEPROM
$eepromhex 'Ask the compiler to generate a hex file suitable for burning EEPROM
Shuzu:
    Data 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9

In the above program, the LCD display result is 4|5|6|7|8|