Atmel

AT89C55J - 8 bit Microcontroller with 20k Bytes Flash

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Features Compatible with MCS-51 Products 20K Bytes of In-System Reprogrammable Flash Memory 4V to 5.5V Operating Range Fully Static Operation: 0 Hz to 24 MHz Three-level Program Memory Lock 256 x 8-bit Internal RAM 32 Programmable I/O Lines Three 16-bit Timer/Counters Eight Interrupt Sources Programmable Serial Channel Low-power Idle and Power-down Mode Interrupt Recovery from Power-down Mode Hardware Watchdog Timer Dual Data Pointer Power-off Flag 40-pin DIP

Pin Description Pin Number Description 1 NC 2 - 9 P1.0 - P1.7 - Port 1 10 RST - Reset 11 P3.0 - Port 3 12 NC 13 - 19 P3.1 - P3.7 - Port 3 20 XTAL2 - Crystal 21 XTAL1 - Crystal 22 GND - Ground 23 NC 24 - 31 P2.0 - P2.7 - Port 2 32 PSEN - Program Store Enable 33 ALE/PROG 34 NC 35 EA/VPP 36 - 43 P0.7 - P0.1 - Port 0 44 Vcc - Positive Power Supply

Pin Layout Dimensional Drawing

Technical Data Data Sheet Atmel - Data Sheet for AT89C55 Application Notes Atmel - 80 Series Application Notes