AT90LS2343 ATMEL [ATMEL Corporation], AT90LS2343 Datasheet - Page 7

• Manufacturer Part Number: AT90LS2343
• Description: 8-Bit Microcontroller with 2K Bytes of In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

Architectural
Overview
1004D–09/01
The fast-access register file concept contains 32 x 8-bit general-purpose working regis-
ters with a single clock cycle access time. This means that during one single clock cycle,
one ALU (Arithmetic Logic Unit) 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-, Y-, and Z-register.
Figure 5. The AT90S2323/2343 AVR RISC Architecture
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 5
shows the AT90S2323/2343 AVR 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 lowermost 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 such 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.
Control Lines
Instruction
Instruction
Program
Decoder
Register
1K x 16
Flash
Program
Counter
AT90S/LS2323/2343
Registers
and Test
Purpose
General
128 x 8
Data Bus 8-bit
Status
SRAM
32 x 8
Data
ALU
Timer/Counter
Watchdog
Registers
EEPROM
I/O Lines
Interrupt
Control
128 x 8
Timer
8-bit
Unit
Unit
SPI
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