ATmega8 Atmel Corporation, ATmega8 Datasheet - Page 226

• Manufacturer Part Number: ATmega8
• Manufacturer: Atmel Corporation

Specifications of ATmega8

• Flash (kbytes): 8 Kbytes
• Pin Count: 32
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 12
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 23
• Ext Interrupts: 2
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Twi (i2c): 1
• Uart: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 1
• Eeprom (bytes): 512
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 2.7 to 5.5
• Operating Voltage (vcc): 2.7 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 3
• Output Compare Channels: 3
• Input Capture Channels: 1
• Pwm Channels: 3
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

Programming the
Fuse High Bits
Programming the Lock
Bits
Reading the Fuse and
Lock Bits
226
ATmega8(L)
The algorithm for programming the Fuse high bits is as follows (refer to
on page 222
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
The algorithm for programming the Lock Bits is as follows (refer to
page 222
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.
The algorithm for reading the Fuse and Lock Bits is as follows (refer to
on page 222
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
3. Set OE to “0”, BS2 to “1”, and BS1 to “1”. The status of the Fuse High bits can now be
4. Set OE to “0”, BS2 to “0”, and BS1 to “1”. The status of the Lock Bits can now be read at
5. Set OE to “1”
Figure 108. Mapping Between BS1, BS2 and the Fuse- and Lock Bits During Read
read at DATA (“0” means programmed)
read at DATA (“0” means programmed)
DATA (“0” means programmed)
for details on Command and Data loading):
for details on Command and Data loading):
for details on Command loading):
Fuse low byte
Fuse high byte
Lock bits
BS2
0
1
BS1
0
1
“Programming the Flash” on
DATA
“Programming the Flash”
“Programming the Flash”
2486Z–AVR–02/11