262
7799D–AVR–11/10
ATmega8U2/16U2/32U2
Table 25-16.
Serial Programming Instruction Set
Instruction
Instruction Format
Operation
Byte 1
Byte 2
Byte 3
Byte4
Programming Enable
1010 1100
0101 0011
xxxx xxxx
Enable Serial Programming after
RESET goes low.
Chip Erase
1010 1100
100x xxxx
xxxx xxxx
Chip Erase EEPROM and Flash.
Load Extended Address Byte
0100 1101
0000 0000
cccc cccc
xxxx xxxx
Defines Extended Address Byte for
Read Program Memory and Write
Program Memory Page.
Read Program Memory
0010 H000
aaaa aaaa
bbbb bbbb
oooo oooo
Read H (high or low) data o from
Program memory at word address
c
:a:b.
Load Program Memory Page
0100 H000
xxxx xxxx
xxbb bbbb
iiii iiii
Write H (high or low) data i to Program
Memory page at word address b. Data
low byte must be loaded before Data
high byte is applied within the same
address.
Write Program Memory Page
0100 1100
aaaa aaaa
bbxx xxxx
xxxx xxxx
Write Program Memory Page at
address c:a:b.
Read EEPROM Memory
1010 0000
0000 aaaa
bbbb bbbb
oooo oooo
Read data o from EEPROM memory at
address a:b.
Write EEPROM Memory
1100 0000
0000 aaaa
bbbb bbbb
iiii iiii
Write data i to EEPROM memory at
address a:b.
Load EEPROM Memory
Page (page access)
1100 0001
0000 0000
0000 00bb
iiii iiii
Load data i to EEPROM memory page
buffer. After data is loaded, program
EEPROM page.
Write EEPROM Memory
Page (page access)
1100 0010
0000 aaaa
bbbb bb00
xxxx xxxx
Write EEPROM page at address a:b.
Read Lock bits
0101 1000
0000 0000
xxxx xxxx
xxoo oooo
Read Lock bits. “0” = programmed, “1”
Write Lock bits
1010 1100
111x xxxx
xxxx xxxx
11ii iiii
Write Lock bits. Set bits = “0” to
Read Signature Byte
0011 0000
000x xxxx
xxxx xxbb
oooo oooo
Read Signature Byte o at address b.
Write Fuse bits
1010 1100
1010 0000
xxxx xxxx
iiii iiii
Set bits = “0” to program, “1” to
unprogram.
Write Fuse High bits
1010 1100
1010 1000
xxxx xxxx
iiii iiii
Set bits = “0” to program, “1” to
unprogram.
Write Extended Fuse Bits
1010 1100
1010 0100
xxxx xxxx
iiii iiii
Set bits = “0” to program, “1” to
unprogram. See
Read Fuse bits
0101 0000
0000 0000
xxxx xxxx
oooo oooo
Read Fuse bits. “0” = programmed, “1”
= unprogrammed.
Read Fuse High bits
0101 1000
0000 1000
xxxx xxxx
oooo oooo
Read Fuse High bits. “0” = pro-
grammed, “1” = unprogrammed.