87C451

Features:

*80C51 based architecture
*Seven 8-bit I/O ports
*Port 6 features:
  Eight data pins
  Four control pins
  Direct MPU bus interface
  Parallel printer interface
*On the microcontroller:
  4k * 8 ROM (83C451) 4k * 8 EPROM (87C451) ROMless version (80C451)
  128 * 8 RAM
  Two 16-bit counter/timers
  Two external interrupts
*External memory addressing capability
  64k ROM and 64k RAM
*Low power consumption:
  Normal operation: less than 24mA at 5V, 12MHz
  Idle mode
  Power-down mode


Pinout




Specifications

PARAMETER	RATING	UNIT
Operating temperature under bias	0 to +70
Storage temperature range	65 to +150
Voltage on any other pin to VSS	0.5 to +6.5	V
Power dissipation (based on package heat transfer limitations, not device power consumption)	1.5	W

NOTES:
1. Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any conditions other than those described in the AC and DC Electrical Characteristics section of this specification is not implied.
2. This product includes circuitry specifically designed for the protection of its internal devices from the damaging effects of excessive static charge. Nonetheless, it is suggested that conventional precautions be taken to avoid applying greater than the rated maxima.
3. Parameters are valid over operating temperature range unless otherwise specified. All voltages are with respect to V_SS  unless otherwise noted.


Description

The Philips 8XC451 is an I/O expanded single-chip microcontroller fabricated with Philips high-density CMOS technology. Philips epitaxial substrate minimizes latch-up sensitivity. The 8XC451 (includes the 80C451, 87C451 and 83C451) is a functional extension of the 87C51 microcontroller with three additional I/O ports and four I/O control lines for a total of 68 pins. Four control lines associated with port 6 facilitate high-speed asynchronous I/O functions.
The 8XC451 includes a 4k × 8 ROM (83C451) EPROM (87C451), a128 × 8 RAM, 56 I/O, two 16-bit timer/counters, a five source, two priority level, nested interrupt structure, a serial I/O port for either a full duplex UART, I/O expansion, or multi-processor communications, and on-chip oscillator and clock circuits.
The80C451 ROMless version includes all of the 83C451 features except the on-board 4k × 8 ROM. The 87C451 has 4k of EPROM on-chip as program memory and is otherwise identical to the 83C451.
The 8XC451 has two software selectable modes of reduced activity for further power reduction; idle mode and power-down mode. Idle mode freezes the CPU while allowing the RAM, timers, serial port,and interrupt system to continue functioning. Power-down mode freezes the oscillator, causing all other chip functions to be inoperative while maintaining the RAM contents.