atmega323l ATMEL Corporation, atmega323l Datasheet - Page 4

• Manufacturer Part Number: atmega323l
• Description: Atmega323 8-bit Avr Microcontroller With 32k Bytes Of In-system Programmable Flash
• Manufacturer: ATMEL Corporation

Pin Descriptions
VCC
GND
Port A (PA7..PA0)
4
ATmega323(L)
The AVR core combines a rich instruction set with 32 general purpose working registers.
All the 32 registers are directly connected to the Arithmetic Logic Unit (ALU), allowing
two independent registers to be accessed in one single instruction executed in one clock
cycle. The resulting architecture is more code efficient while achieving throughputs up to
ten times faster than conventional CISC microcontrollers.
The ATmega323 provides the following features: 32K bytes of In-System Programmable
Flash, 1K bytes EEPROM, 2K bytes SRAM, 32 general purpose I/O lines, 32 general
purpose working registers, a JTAG interface for Boundary-Scan, On-chip Debugging
support and programming, three flexible Timer/Counters with compare modes, internal
and external interrupts, a serial programmable USART, a byte oriented Two-wire Serial
Interface, an 8-channel, 10-bit ADC, a programmable Watchdog Timer with internal
Oscillator, an SPI serial port, and six software selectable power saving modes. The Idle
mode stops the CPU while allowing the SRAM, Timer/Counters, SPI port, and interrupt
system to continue functioning. The Power-down mode saves the register contents but
freezes the Oscillator, disabling all other chip functions until the next interrupt or Hard-
ware Reset. In Power-save mode, the asynchronous timer continues to run, allowing the
user to maintain a timer base while the rest of the device is sleeping. The ADC Noise
Reduction mode stops the CPU and all I/O modules except asynchronous timer and
ADC, to minimize switching noise during ADC conversions. In Standby mode, the crys-
tal/resonator Oscillator is running while the rest of the device is sleeping. This allows
very fast start-up combined with low-power consumption. In Extended Standby mode,
both the main Oscillator and the asynchronous timer continue to run.
The device is manufactured using Atmel’s high-density non-volatile memory technology.
The On-chip ISP Flash allows the Program memory to be re-programmed In-System
through an SPI serial interface, by a conventional non-volatile memory programmer, or
by an On-chip Boot Program running on the AVR core. The Boot Program can use any
interface to download the application program in the Application Flash memory. By com-
bining an 8-bit RISC CPU with In-System Programmable Flash on a monolithic chip, the
Atmel ATmega323 is a powerful microcontroller that provides a highly flexible and cost
effective solution to many embedded control applications.
The ATmega323 AVR is supported with a full suite of program and system development
tools including: C compilers, macro assemblers, program debugger/simulators, In-Cir-
cuit Emulators, and evaluation kits.
Digital supply voltage.
Digital ground.
Port A serves as the analog inputs to the A/D Converter.
Port A also serves as an 8-bit bi-directional I/O port, if the A/D Converter is not used.
Port pins can provide internal pull-up resistors (selected for each bit). The Port A output
buffers can sink 20 mA and can drive LED displays directly. When pins PA0 to PA7 are
used as inputs and are externally pulled low, they will source current if the internal pull-
up resistors are activated. The Port A pins are tri-stated when a reset condition
becomes active, even if the clock is not running.
1457G–AVR–09/03