Description The AT90S2333/4433 is a low-power CMOS 8-bit microcontroller based on the AVR RISC architecture. By executing pow- erful instructions in a single clock cycle, the AT90S2333/4433 achieves throughputs approaching 1 MIPS per MHz allowing the system designer to optimize power consumption versus processing speed. 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 AT90S2333/4433 provides the following features: 2K/4K bytes of In-System Programmable Flash, 128/256 bytes EEPROM, 128 bytes SRAM, 20 general purpose I/O lines, 32 general purpose working registers, two flexible timer/counters with compare modes, internal and external interrupts, a programmable serial UART, 6-channel, 10-bit ADC, programmable Watchdog Timer with internal oscillator, an SPI serial port and two software selectable power saving modes. The Idle mode stops the CPU while allowing the SRAM, timer/counters, SPI port and interrupt system to continue function- ing. The Power Down mode saves the register contents but freezes the oscillator, disabling all other chip functions until the next interrupt or hardware reset. The device is manufactured using Atmel’s high density nonvolatile memory technology. The on-chip Flash program mem- ory can be reprogrammed in-system through an SPI serial interface or by a conventional nonvolatile memory programmer. By combining a RISC 8-bit CPU with In-System Programmable Flash on a monolithic chip, the Atmel AT90S2333/4433 is a powerful microcontroller that provides a highly flexible and cost effective solution to many embedded control applications. The AT90S2333/4433 AVR is supported with a full suite of program and system development tools including: C compilers, macro assemblers, program debugger/simulators, in-circuit emulators, and evaluation kits. Table 1. Comparison Table DeviceFlashEEPROMSRAMVoltage RangeFrequency AT90S2333 2K 128B 128B 4.0V - 6.0V 0 - 8 MHz AT90LS2333 2K 128B 128B 2.7V - 6.0V 0 - 4 MHz AT90S4433 4K 256B 128B 4.0V - 6.0V 0 - 8 MHz AT90LS4433 4K 256B 128B 2.7V - 6.0V 0 - 4 MHz 2AT90S/LS2333 and AT90S/LS4433 Document Outline Features Description Block Diagram Pin Descriptions VCC GND Port B (PB5..PB0) Port C (PC5..PC0) Port D (PD7..PD0) RESET XTAL1 XTAL2 AVCC AREF AGND Architectural Overview Register Summary (Continued) Instruction Set Summary (Continued) Ordering Information Pin Configurations