Atmel AT89C55 free download

File name 89C55.PDF

AT89C55 Features · Compatible with MCS-51TM Products · 20K Bytes of In-System Reprogrammable Flash Memory · · · · · · · ­ Endurance: 1,000 Write/Erase Cycles Fully Static Operation: 0 Hz to 33 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 Low Power Idle and Power Down Modes Description The AT89C55 is a low-power, high-performance CMOS 8-bit microcomputer with 20K bytes of Flash programmable and erasable read only memory. The device is manufactured using Atmel's high density nonvolatile memory technology and is compatible with the industry standard 80C51 instruction set and pinout. The on-chip Flash allows the program memory to be reprogrammed in-system or by a conventional nonvolatile memory programmer. By combining a versatile 8-bit CPU with Flash on a monolithic chip, the Atmel AT89C55 is a powerful microcomputer which provides a highly flexible and cost effective solution to many embedded control applications. (continued) 8-Bit Microcontroller with 20K Bytes Flash AT89C55 Pin Configurations PDIP PQFP/TQFP PLCC 0580D-A­12/97 4-169 Block Diagram P0.0 - P0.7 P2.0 - P2.7 VCC PORT 0 DRIVERS GND PORT 2 DRIVERS RAM ADDR. REGISTER RAM PORT 0 LATCH PORT 2 LATCH FLASH B REGISTER ACC STACK POINTER PROGRAM ADDRESS REGISTER BUFFER TMP2 TMP1 ALU INTERRUPT, SERIAL PORT, AND TIMER BLOCKS PC INCREMENTER PSW PROGRAM COUNTER PSEN ALE/PROG EA / VPP RST PORT 1 LATCH PORT 3 LATCH TIMING AND CONTROL INSTRUCTION REGISTER DPTR OSC PORT 1 DRIVERS PORT 3 DRIVERS P1.0 - P1.7 P3.0 - P3.7 4-170 AT89C55 AT89C55 The AT89C55 provides the following standard features: 20K bytes of Flash, 256-bytes of RAM, 32 I/O lines, three 16-bit timer/counters, a six-vector two-level interrupt architecture, a full duplex serial port, on-chip oscillator, and clock circuitry. In addition, the AT89C55 is designed with static logic for operation down to zero frequency and supports two software selectable power saving modes. The Idle Mode stops the CPU while allowing the RAM, timer/counters, serial port, and interrupt system to continue functioning. The Power Down Mode saves the RAM contents but freezes the oscillator, disabling all other chip functions until the next hardware reset. The low-voltage option saves power and operates with a 2.7-volt power supply. Port 2 Port 2 is an 8-bit bidirectional I/O port with internal pullups. The Port 2 output buffers can sink/source four TTL inputs. When 1s are written to Port 2 pins, they are pulled high by the internal pullups and can be used as inputs. As inputs, Port 2 pins that are externally being pulled low will source current (IIL) because of the internal pullups. Port 2 emits the high-order address byte during fetches from external program memory and during accesses to external data memory that use 16-bit addresses (MOVX @ DPTR). In this application, Port 2 uses strong internal pullups when emitting 1s. During accesses to ex