ATMEGA8_08 Datasheet, PDF (302/308 Pages) ATMEL Corporation – 8-bit with 8K Bytes In-System Programmable Flash

More details regarding use of the TWI bit rate prescaler and a Table 65, “TWI Bit Rate Pres-
caler,” on page 173.
Changes from Rev. 1. Updated Typical Start-up Times.
2486C-03/02 to
The following tables has been updated:
Rev. 2486D-03/02
Table 5, “Start-up Times for the Crystal Oscillator Clock Selection,” on page 28, Table 6,
“Start-up Times for the Low-frequency Crystal Oscillator Clock Selection,” on page 28,
Table 8, “Start-up Times for the External RC Oscillator Clock Selection,” on page 29, and
Table 12, “Start-up Times for the External Clock Selection,” on page 32.
2. Added “ATmega8 Typical Characteristics” on page 249.
Changes from Rev. 1. Updated TWI Chapter.
2486B-12/01 to
More details regarding use of the TWI Power-down operation and using the TWI as Master
Rev. 2486C-03/02
with low TWBRR values are added into the datasheet.
Added the note at the end of the “Bit Rate Generator Unit” on page 170.
Added the description at the end of “Address Match Unit” on page 170.
2. Updated Description of OSCCAL Calibration Byte.
In the datasheet, it was not explained how to take advantage of the calibration bytes for 2, 4,
and 8 MHz Oscillator selections. This is now added in the following sections:
Improved description of “Oscillator Calibration Register – OSCCAL” on page 31 and “Cali-
bration Byte” on page 225.
3. Added Some Preliminary Test Limits and Characterization Data.
Removed some of the TBD’s in the following tables and pages:
Table 3 on page 26, Table 15 on page 38, Table 16 on page 42, Table 17 on page 44, “T_A =
-40°C to 85°C, V_CC = 2.7V to 5.5V (unless otherwise noted)” on page 242, Table 99 on page
244, and Table 102 on page 246.
4. Updated Programming Figures.
Figure 104 on page 226 and Figure 112 on page 237 are updated to also reflect that AV_CC
must be connected during Programming mode.
5. Added a Description on how to Enter Parallel Programming Mode if RESET Pin is Dis-
abled or if External Oscillators are Selected.
Added a note in section “Enter Programming Mode” on page 228.
302 ATmega8(L)
2486T–AVR–05/08