87C51 Selling Leads

Description: This circuit utilizes an 87C57 microcontroller along with several peripherals to convert X-10 power-line carrier-code formats from a personal computer for use with an X-10 power-line interface in a home control system. Software details can be found in the reference. The CMOS 8XC51 microcontroller is functionally compatible with the NMOS 8031/8051 microcontrollers. The Philips CMOS technology merges the high-speed and density features of HMOS with the low power characteristics of CMOS. The use of a Philips epitaxial substrate reduces latch-up sensitivity. The 8XC51 includes a 4k x 8 ROM (80C51) EPROM (87C51), a 128 x 8 RAM, 32 I/O lines, two 16-bit counter/timers, a five-source, two-priority level nested interrupt structure, a serial I/O port for multi-processor communications, I/O expansion, or full duplex UART, and integrated oscillator and clock circuits. Furthermore, the device offers two software-selectable power reduction modes: idle mode and power-down mode. In idle mode, the CPU is halted while the RAM, timers, serial port, and interrupt system remain operational. The power-down mode retains the RAM contents but halts the oscillator, rendering all other chip functions inactive.

The circuit design features a robust integration of the 87C57 microcontroller, which serves as the central processing unit for managing X-10 power-line communications. The microcontroller is interfaced with a personal computer to facilitate the encoding and decoding of power-line carrier codes, which are essential for controlling home appliances remotely. The design leverages the high-density and low-power characteristics of the CMOS 8XC51 architecture, ensuring efficient operation while minimizing energy consumption.

At the heart of the circuit, the 4k x 8 ROM and 128 x 8 RAM provide essential memory resources for program storage and data handling. This memory configuration supports the execution of complex algorithms necessary for processing X-10 commands. The 32 I/O lines enable extensive connectivity with various peripherals, allowing for flexible system expansion and integration with additional home automation devices.

The inclusion of two 16-bit counter/timers enhances the microcontroller's capability to manage time-sensitive tasks, such as generating precise timing signals for communication protocols. The nested interrupt structure, which supports multiple sources and priority levels, ensures that the microcontroller can efficiently handle various events without missing critical signals, thus maintaining the responsiveness of the home control system.

The serial I/O port is particularly noteworthy, as it facilitates multi-processor communications and can be configured for full duplex operation, making it suitable for complex networking scenarios. The integrated oscillator and clock circuits provide stable timing references for the entire system, ensuring reliable operation.

Additionally, the power management features of the 8XC51 are crucial for applications where energy efficiency is paramount. The idle mode allows the system to conserve power while maintaining essential functions, whereas the power-down mode ensures that the microcontroller can quickly resume operation without losing critical data. These features make the circuit well-suited for applications in home automation, where prolonged battery life and efficient energy use are highly desirable.This circuit uses an 87C57 microcontroller and a few peripherals to condition X-10 power-line carrier-code formats from a personal computer to use an X-10 power-line interface in a home-control system. Software details are available in the reference. technology. The CMOS 8XC51 is functionally compatible with the NMOS 8031/8051 microcontrollers. Th e Philips CMOS technology combines the high speed and density characteristics of HMOS with the low power attributes of CMOS. Philips epitaxial substrate minimizes latch-up sensitivity. The 8XC51 contains a 4k * 8 ROM (80C51) EPROM (87C51), a 128* 8 RAM, 32 I/O lines, two 16-bit counter/timers, a five-source, two-priority level nested interrupt structure, a serial I/O port for either multi-processor communications, I/O expansion or full duplex UART, and on-chip oscillator and clock circuits.

In addition, the device has two software selectable modes of power reduction-idle mode and power-down mode. The idle mode freezes the CPU while allowing the RAM, timers, serial port, and interrupt system to continue functioning.

The power-down mode saves the RAM contents but freezes the oscillator, causing all other chip functions to be inoperative.