Datasheet

270
2466T–AVR–07/10
ATmega16(L)
Programming the
Fuse High Bits
The algorithm for programming the Fuse high bits is as follows (refer to “Programming the Flash”
on page 266 for details on Command and Data loading):
1. A: Load Command “0100 0000”.
2. C: Load Data Low Byte. Bit n = “0” programs and bit n = “1” erases the Fuse bit.
3. Set BS1 to “1” and BS2 to “0”. This selects high data byte.
4. Give WR
a negative pulse and wait for RDY/BSY to go high.
5. Set BS1 to “0”. This selects low data byte.
Figure 131. Programming the Fuses
Programming the Lock
Bits
The algorithm for programming the Lock bits is as follows (refer to “Programming the Flash” on
page 266 for details on Command and Data loading):
1. A: Load Command “0010 0000”.
2. C: Load Data Low Byte. Bit n = “0” programs the Lock bit.
3. Give WR
a negative pulse and wait for RDY/BSY to go high.
The Lock bits can only be cleared by executing Chip Erase.
Reading the Fuse and
Lock Bits
The algorithm for reading the Fuse and Lock bits is as follows (refer to “Programming the Flash”
on page 266 for details on Command loading):
1. A: Load Command “0000 0100”.
2. Set OE
to “0”, BS2 to “0” and BS1 to “0”. The status of the Fuse Low bits can now be
read at DATA (“0” means programmed).
3. Set OE
to “0”, BS2 to “1” and BS1 to “1”. The status of the Fuse High bits can now be
read at DATA (“0” means programmed).
4. Set OE
to “0”, BS2 to “0” and BS1 to “1”. The status of the Lock bits can now be read at
DATA (“0” means programmed).
5. Set OE
to “1”.
RDY/BSY
WR
OE
RESET +12V
PAGEL
$40
DATA
DATA XX
XA1
XA0
BS1
XTAL1
AC
$40 DATA XX
AC
Write Fuse Low byte Write Fuse high byte
BS2