317
2467S–AVR–07/09
ATmega128
Programming the
Fuses
1.
Enter JTAG instruction PROG_COMMANDS.
2.
Enable Fuse write using programming instruction 6a.
3.
Load data byte using programming instructions 6b. A bit value of “0” will program the cor-
responding fuse, a “1” will unprogram the fuse.
4.
Write Extended Fuse byte using programming instruction 6c.
5.
Poll for Fuse write complete using programming instruction 6d, or wait for t
WLRH
(refer to
6.
Load data byte using programming instructions 6e. A bit value of “0” will program the cor-
responding fuse, a “1” will unprogram the fuse.
7.
Write Fuse high byte using programming instruction 6f.
8.
Poll for Fuse write complete using programming instruction 6g, or wait for t
WLRH
(refer to
9.
Load data byte using programming instructions 6h. A “0” will program the fuse, a “1” will
unprogram the fuse.
10. Write Fuse low byte using programming instruction 6i.
11. Poll for Fuse write complete using programming instruction 6j, or wait for t
WLRH
(refer to
Programming the Lock
Bits
1.
Enter JTAG instruction PROG_COMMANDS.
2.
Enable Lock bit write using programming instruction 7a.
3.
Load data using programming instructions 7b. A bit value of “0” will program the corre-
sponding lock bit, a “1” will leave the lock bit unchanged.
4.
Write Lock bits using programming instruction 7c.
5.
Poll for Lock bit write complete using programming instruction 7d, or wait for t
WLRH
(refer
).
Reading the Fuses
and Lock Bits
1.
Enter JTAG instruction PROG_COMMANDS.
2.
Enable Fuse/Lock bit read using programming instruction 8a.
3.
To read all Fuses and Lock bits, use programming instruction 8f.
To only read Extended Fuse byte, use programming instruction 8b.
To only read Fuse high byte, use programming instruction 8c.
To only read Fuse low byte, use programming instruction 8d.
To only read Lock bits, use programming instruction 8e.
Reading the Signature
Bytes
1.
Enter JTAG instruction PROG_COMMANDS.
2.
Enable Signature byte read using programming instruction 9a.
3.
Load address $00 using programming instruction 9b.
4.
Read first signature byte using programming instruction 9c.
5.
Repeat steps 3 and 4 with address $01 and address $02 to read the second and third
signature bytes, respectively.
Reading the
Calibration Byte
1.
Enter JTAG instruction PROG_COMMANDS.
2.
Enable Calibration byte read using programming instruction 10a.
3.
Load address $00 using programming instruction 10b.
4.
Read the calibration byte using programming instruction 10c.