Datasheet

Instruction TDI sequence TDO sequence Notes
8f. Read Fuses and Lock bits 0111010_00000000
0111110_00000000
0110010_00000000
0110110_00000000
0110111_00000000
xxxxxxx_xxxxxxxx
xxxxxxx_oooooooo
xxxxxxx_oooooooo
xxxxxxx_oooooooo
xxxxxxx_oooooooo
(5)
fuse ext. byte
fuse high byte
fuse low byte
lock bits
9a. Enter Signature Byte Read 0100011_00001000 xxxxxxx_xxxxxxxx
9b. Load Address Byte 0000011_bbbbbbbb xxxxxxx_xxxxxxxx
9c. Read Signature Byte 0110010_00000000
0110011_00000000
xxxxxxx_xxxxxxxx
xxxxxxx_oooooooo
10a. Enter Calibration Byte Read 0100011_00001000 xxxxxxx_xxxxxxxx
10b. Load Address Byte 0000011_bbbbbbbb xxxxxxx_xxxxxxxx
10c. Read Calibration Byte 0110110_00000000
0110111_00000000
xxxxxxx_xxxxxxxx
xxxxxxx_oooooooo
11a. Load No Operation Command 0100011_00000000
0110011_00000000
xxxxxxx_xxxxxxxx
xxxxxxx_xxxxxxxx
Note:
1. This command sequence is not required if the seven MSB are correctly set by the previous
command sequence (which is normally the case).
2. Repeat until o = “1”.
3. Set bits to “0” to program the corresponding fuse, “1” to unprogram the Fuse.
4. Set bits to “0” to program the corresponding lock bit, “1” to leave the Lock bit unchanged.
5. “0” = programmed, “1” = unprogrammed.
6. The bit mapping for Fuses Extended byte is listed in Extended Fuse Byte table of Fuse Bits section.
7. The bit mapping for Fuses High byte is listed in Fuse High Byte table of Fuse Bits section.
8. The bit mapping for Fuses Low byte is listed in Fuse Low Byte table of Fuse Bits section.
9. The bit mapping for Lock bits byte is listed in Lock Bit Byte table of Program and Data Memory Lock
Bits section.
10. Address bits exceeding PCMSB and EEAMSB (Command Byte Bit Coding in Signal Names section
and Page Size section) are don’t care
Atmel ATmega644A [DATASHEET]
Atmel-42716C-ATmega644A_Datasheet_Complete-10/2016
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