Rainbow Electronics ATmega128L - Manual (Page 309)

309
ATmega128(L)
2467B–09/01
Programming the Fuses 1. Enter JTAG instruction PROG_COMMANDS.
2. Enable Fuse write using programming instruction 6a.
3. Load data high byte using programming instructions 6b. A bit value of “0” will pro-
gram the corresponding fuse, a “1” will unprogram the fuse.
4. Write Fuse high byte using programming instruction 6c.
5. Poll for Fuse write complete using programming instruction 6d, or wait for t
WLRH
(refer to Table Note: on page 291).
6. Load data low byte using programming instructions 6e. A “0” will program the
fuse, a “1” will unprogram the fuse.
7. Write Fuse low byte using programming instruction 6f.
8. Poll for Fuse write complete using programming instruction 6g, or wait for t
WLRH
(refer to Table Note: on page 291).
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
corresponding 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 to Table Note: on page 291).
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 8e.
To only read Fuse high byte, use programming instruction 8b.
To only read Fuse low byte, use programming instruction 8c.
To only read Lock bits, use programming instruction 8d.
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.