
301
2593O–AVR–02/12
ATmega644
stored until the command is re-issued, that is, the command needs only be issued for the
first page, and when crossing the 64KWord boundary.
7.
At the end of the programming session, RESET can be set high to commence normal
operation.
8.
Power-off sequence (if needed):
Set RESET to “1”.
Turn V
CC power off.
25.9
Serial Programming Instruction set
Table 25-16. Minimum Wait Delay Before Writing the Next Flash or EEPROM Location
Symbol
Minimum Wait Delay
tWD_FLASH
4.5 ms
tWD_EEPROM
9.0 ms
t
WD_ERASE
9.0 ms
Table 25-17. Serial Programming Instruction Set (Hexadecimal values)
Instruction/Operation
Instruction Format
Byte 1
Byte 2
Byte 3
Byte 4
Programming Enable
$AC
$53
$00
Chip Erase (Program Memory/EEPROM)
$AC
$80
$00
Poll RDY/BSY
$F0
$00
data byte out
Load Instructions
Load Extended Address byte
(1)$4D
$00
Extended adr
$00
Load Program Memory Page, High byte
$48
$00
adr LSB
high data byte in
Load Program Memory Page, Low byte
$40
$00
adr LSB
low data byte in
Load EEPROM Memory Page (page access)
$C1
$00
0000 000aa
data byte in
Read Instructions
Read Program Memory, High byte
$28
adr MSB
adr LSB
high data byte out
Read Program Memory, Low byte
$20
adr MSB
adr LSB
low data byte out
Read EEPROM Memory
$A0
0000 00aa
aaaa aaaa
data byte out
Read Lock bits
$58
$00
data byte out
Read Signature Byte
$30
$00
0000 000aa
data byte out
Read Fuse bits
$50
$00
data byte out
Read Fuse High bits
$58
$08
$00
data byte out
Read Extended Fuse Bits
$50
$08
$00
data byte out
Read Calibration Byte
$38
$00
data byte out
Write Instructions
Write Program Memory Page
$4C
adr MSB
adr LSB
$00
Write EEPROM Memory
$C0
0000 00aa
aaaa aaaa
data byte in