Datasheet
31.6.3. Chip Erase
The Chip Erase will erase the Flash and EEPROM memories plus Lock bits. The Lock bits are not reset
until the program memory has been completely erased. The Fuse bits are not changed. A Chip Erase
must be performed before the Flash and/or EEPROM are reprogrammed.
Note: The EEPRPOM memory is preserved during Chip Erase if the EESAVE Fuse is programmed.
Load Command “Chip Erase”:
1. Set XA1, XA0 to “10”. This enables command loading.
2. Set BS1 to “0”.
3. Set DATA to “1000 0000”. This is the command for Chip Erase.
4. Give XTAL1 a positive pulse. This loads the command.
5. Give
WR a negative pulse. This starts the Chip Erase. RDY/BSY goes low.
6. Wait until RDY/BSY goes high before loading a new command.
31.6.4. Programming the Flash
The Flash is organized in pages. When programming the Flash, the program data is latched into a page
buffer. This allows one page of program data to be programmed simultaneously. The following procedure
describes how to program the entire Flash memory:
Step A. Load Command “Write Flash”.
1. Set XA1, XA0 to “10”. This enables command loading.
2. Set BS1 to “0”.
3. Set DATA to “0001 0000”. This is the command for Write Flash.
4. Give XTAL1 a positive pulse. This loads the command.
Step B. Load Address Low Byte.
1. Set XA1, XA0 to “00”. This enables address loading.
2. Set BS1 to “0”. This selects low address.
3. Set DATA = Address low byte (0x00 - 0xFF).
4. Give XTAL1 a positive pulse. This loads the address low byte.
Step C. Load Data Low Byte.
1. Set XA1, XA0 to “01”. This enables data loading.
2. Set DATA = Data low byte (0x00 - 0xFF).
3. Give XTAL1 a positive pulse. This loads the data byte.
Step D. Load Data High Byte.
1. Set BS1 to “1”. This selects high data byte.
2. Set XA1, XA0 to “01”. This enables data loading.
3. Set DATA = Data high byte (0x00 - 0xFF).
4. Give XTAL1 a positive pulse. This loads the data byte.
Step E. Latch Data.
1. Set BS1 to “1”. This selects high data byte.
2. Give PAGEL a positive pulse. This latches the data bytes. (Refer to figure Programming the Flash
Waveforms in this section for signal waveforms)
Atmel ATmega64A [DATASHEET]
Atmel-8160E-ATmega64A_Datasheet_Complete-09/2015
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