ATA6020N ATMEL Corporation, ATA6020N Datasheet - Page 3

• Manufacturer Part Number: ATA6020N
• Description: Low-current Microcontroller For Watchdog Function
• Manufacturer: ATMEL Corporation

3. Introduction
4. MARC4 Architecture General Description
4708D–4BMCU–09/05
The ATA6020N is a member of Atmel’s 4-bit single-chip microcontroller family. It contains ROM,
RAM, parallel I/O ports, one 8-bit programmable multifunction timer/counter, voltage supervisor,
interval timer with watchdog function and a sophisticated on-chip clock generation with inte-
grated RC-oscillators.
The MARC4 microcontroller consists of an advanced stack-based, 4-bit CPU core and on-chip
peripherals. The CPU is based on the HARVARD architecture with physically separated pro-
gram memory (ROM) and data memory (RAM). Three independent buses, the instruction bus,
the memory bus and the I/O bus, are used for parallel communication between ROM, RAM and
peripherals. This enhances program execution speed by allowing both instruction prefetching,
and a simultaneous communication to the on-chip peripheral circuitry. The extremely powerful
integrated interrupt controller with associated eight prioritized interrupt levels supports fast and
efficient processing of hardware events. The MARC4 is designed for the high-level programming
language qFORTH. The core includes both, an expression and a return stack. This architecture
enables high-level language programming without any loss of efficiency or code density.
Figure 4-1.
System
Reset
clock
MARC4 Core
Clock
Sleep
Reset
Program
memory
On-chip peripheral modules
Instruction
controller
Interrupt
decoder
Instruction
bus
I/O bus
MARC4 CORE
PC
Memory bus
CCR
SP
RP
Y
X
TOS
ALU
256 x 4-bit
RAM
ATA6020N
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