IC AT89C1051
The AT89C1051 is a low-
voltage, high-performance CMOS 8-bit microcomputer with 1 Kbyte of Flash programmable and erasable read only memory (PEROM).
The device is manufactured using Atmel’s high density nonvolatile memory technology and is compatible with the industry standard MCS-51Ô instruction set and pinout. By combining a versatile 8-bit CPU with Flash on a monolithic chip, the Atmel AT89C1051 is a powerful microcomputer which provides a highly flexible and cost effective solution to many embedded control applications.
The AT89C1051 provides the following standard features: 1 Kbyte of Flash, 64 bytes of RAM, 15 I/O lines, one 16-bit timer/counter, a three vector two-level interrupt architecture, a precision analog comparator, on-chip oscillator and clock circuitry. In addition, the AT89C1051 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.
Diagram Block AT89C1051
XTAL1 and XTAL2 are the input and output, respectively, of an inverting amplifier which can be configured for use as an on-chip oscillator. Either a quartz crystal or ceramic resonator may be used. To drive the device from an external clock source, XTAL2 should be left unconnected while XTAL1. There are no requirements on the duty cycle of the external clock signal, since the input to the internal clocking circuitry is through a divide-by-two flip-flop, but minimum and maximum
voltage high and low time specifications must be observed.