3
ATmega103(L)
0945G–09/01
Description
The ATmega103(L) is a low-power, CMOS, 8-bit microcontroller based on the AVR
RISC architecture. By executing powerful instructions in a single clock cycle, the
ATmega103(L) achieves throughputs approaching 1 MIPS per MHz, allowing the sys-
tem designer to optimize power consumption versus processing speed.
The AVR core is based on an enhanced RISC architecture that combines a rich instruc-
tion 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 architec-
ture is more code efficient while achieving throughputs up to ten times faster than
conventional CISC microcontrollers.
The ATmega103(L) provides the following features: 128K bytes of In-System Program-
mable Flash, 4K bytes EEPROM, 4K bytes SRAM, 32 general-purpose I/O lines, 8 input
lines, 8 output lines, 32 general-purpose working registers, real-time counter (RTC), 4
flexible timer/counters with compare modes and PWM, UART, programmable watchdog
timer with internal oscillator, an SPI serial port and 3 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 inter-
rupt or hardware reset. In Power-save mode, the timer oscillator continues to run,
allowing the user to maintain a timer base while the rest of the device is sleeping.
The device is manufactured using Atmel’s high-density nonvolatile memory technology.
The On-chip ISP Flash allows the program memory to be reprogrammed in-system
through a serial interface or by a conventional nonvolatile memory programmer. By
combining an 8-bit RISC CPU with a large array of ISP Flash on a monolithic chip, the
Atmel ATmega103(L) is a powerful microcontroller that provides a highly flexible and
cost-effective solution to many embedded control applications.
The ATmega103(L) AVR is supported with a full suite of program and system develop-
ment tools including: C compilers, macro assemblers, program debugger/simulators, in-
circuit emulators and evaluation kits.