Rainbow Electronics ATmega163L - Manual (Page 7)

ATmega163(L)
7
Architectural Overview
The fast-access register file concept contains 32 x 8-bit general purpose working registers 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-bits 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 look-up tables in
Flash program memory. These added function registers are the 16-bits X-register, Y-register, and Z-register.
The ALU supports arithmetic and logic operations between registers or between a constant and a register. Single register
operations are also executed in the ALU. Figure 5 shows the ATmega163 AVR Enhanced RISC microcontroller
architecture.
In addition to the register operation, the conventional memory addressing modes can be used on the register file as well.
This is enabled by the fact that the register file is assigned the 32 lowest Data Space addresses ($00 - $1F), allowing them
to be accessed as though they were ordinary memory locations.
The I/O memory space contains 64 addresses for CPU peripheral functions as Control Registers, Timer/Counters, A/D-
converters, and other I/O functions. The I/O Memory can be accessed directly, or as the Data Space locations following
those of the register file, $20 - $5F.
Figure 5. The ATmega163 AVR RISC Architecture
8K X 16
Program
Memory
Instruction
Register
Instruction
Decoder
Program
Counter
Control Lines
32 x 8
General
Purpose
Registrers
ALU
Status
and Control
Interrupt
Unit
SPI
Unit
8-bit
Timer/Counter
Watchdog
Timer
A/D Converter
Analog
Comparator
32
I/O Lines
512 x 8
EEPROM
Data Bus 8-bit
AVR ATmega163 Architecture
2-Wire Serial
Interface
16-bit
Timer/Counter
with PWM
8-bit
Timer/Counter
with PWM
1024 x 8
Data
SRAM
Direct Addressing Indirect Addressing
Serial
UART