Datasheet

31.5. Page Size
Table 31-7 Number of Words in a Page and number of Pages in the Flash
Flash Size Page Size PCWORD Number of Pages PCPAGE PCMSB
32K words (64K bytes) 128 words PC[6:0] 256 PC[14:7] 14
Table 31-8 Number of Words in a Page and number of Pages in the EEPROM
EEPROM Size Page Size PCWORD Number of Pages PCPAGE EEAMSB
2K bytes 8 bytes EEA[2:0] 256 EEA[8:2] 10
31.6. Parallel Programming
31.6.1. Enter Programming Mode
The following algorithm puts the device in Parallel Programming mode:
1. Apply 4.5 - 5.5V between V
CC
and GND, and wait at least 100µs.
2. Set RESET to “0” and toggle XTAL1 at least 6 times
3. Set the Prog_enable pins listed in Table 31-10 Pin Values Used to Enter Programming Mode on
page 395 to “0000” and wait at least 100ns.
4. Apply 11.5 - 12.5V to RESET. Any activity on Prog_enable pins within 100ns after +12V has been
applied to RESET, will cause the device to fail entering Programming mode.
Note, if External Crystal or External RC configuration is selected, it may not be possible to apply qualified
XTAL1 pulses. In such cases, the following algorithm should be followed:
1. Set Prog_enable pins listed in Table 31-10 Pin Values Used to Enter Programming Mode on page
395 to “0000”.
2. Apply 4.5 - 5.5V between V
CC
and GND simultaneously as 11.5 - 12.5V is applied to RESET.
3. Wait 100μs.
4. Re-program the fuses to ensure that External Clock is selected as clock source (CKSEL3:0 =
0b0000). If Lock bits are programmed, a Chip Erase command must be executed before changing
the fuses.
5. Exit Programming mode by power the device down or by bringing RESET pin to 0b0.
6. Entering Programming mode with the original algorithm, as described above.
31.6.2. Considerations for Efficient Programming
The loaded command and address are retained in the device during programming. For efficient
programming, the following should be considered.
• The command needs only be loaded once when writing or reading multiple memory locations.
• Skip writing the data value 0xFF, that is the contents of the entire EEPROM (unless the EESAVE
Fuse is programmed) and Flash after a Chip Erase.
• Address high byte needs only be loaded before programming or reading a new 256 word window in
Flash or 256byte EEPROM. This consideration also applies to Signature bytes reading.
Atmel ATmega64A [DATASHEET]
Atmel-8160E-ATmega64A_Datasheet_Complete-09/2015
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