atmega161-4pi ATMEL Corporation, atmega161-4pi Datasheet - Page 18

• Manufacturer Part Number: atmega161-4pi
• Description: 8-bit Microcontroller With 16k Bytes Of In-system Programmable Flash
• Manufacturer: ATMEL Corporation

18
ATmega161(L)
Figure 21. The Parallel Instruction Fetches and Instruction Executions
Figure 22 shows the internal timing concept for the Register File. In a single clock cycle
an ALU operation using two register operands is executed and the result is stored back
to the destination register.
Figure 22. Single Cycle ALU Operation
The internal data SRAM access is performed in two System Clock cycles as described
in Figure 23.
Figure 23. On-chip Data SRAM Access Cycles
2nd Instruction Execute
Register Operands Fetch
3rd Instruction Execute
1st Instruction Execute
ALU Operation Execute
2nd Instruction Fetch
System Clock Ø
3rd Instruction Fetch
4th Instruction Fetch
1st Instruction Fetch
Total Execution Time
Result Write Back
System Clock Ø
System Clock Ø
Address
Data
Data
WR
RD
Prev. Address
T1
T1
T1
Address
T2
T2
T2
T3
T3
T3
T4
1228D–AVR–02/07
T4
T4