atmega161-4pi ATMEL Corporation, atmega161-4pi Datasheet - Page 7

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

Architectural
Overview
1228D–AVR–02/07
The fast-access Register File concept contains 32 x 8-bit general purpose working reg-
isters with a single clock cycle access time. This means that during one single clock
cycle, one Arithmetic Logic Unit (ALU) operation is executed. Two operands are output
from the Register File, the operation is executed and the result is stored back in the
Register File – in one clock cycle.
Six of the 32 registers can be used as three 16-bit indirect address register pointers for
Data Space addressing – enabling efficient address calculations. One of the three
address pointers is also used as the address pointer for the constant table look-up func-
tion. These added function registers are the 16-bit X-register, Y-register and Z-register.
The ALU supports arithmetic and logic functions between registers or between a con-
stant and a register. Single register operations are also executed in the ALU. Figure 4
shows the ATmega161 AVR RISC microcontroller architecture.
Figure 4. The ATmega161 AVR RISC Architecture
Control Lines
Instruction
Instruction
Program
Register
Decoder
8K x 16
Memory
Program
Counter
and Control
Registers
EEPROM
I/O Lines
1024 x 8
Purpose
General
512 x 8
Data Bus 8-bit
SRAM
Status
32 x 8
Data
ALU
32
ATmega161(L)
Timer/Counter
Timer/Counter
Timer/Counter
Comparator
with PWM
with PWM
with PWM
Watchdog
and RTC
Interrupt
Analog
UART0
Serial
Timer
16-bit
UART1
Serial
8-bit
8-bit
Unit
Unit
SPI
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