阐述了一个由上位PC机和AT89C52下位单片机组成的主从分布式温度巡回检测系统。主从机采用RS-485 串行通讯标准进行通信，可在下位单片机实现基本的温度数据巡回检测基础上，由上位PC机实现综合处理功能或扩展为远程操作。整个系统具有巡检速度快，扩展性好的特点。
Abstract:
In this paper,a top PC and AT89C52 u ...
The PCA9674/74A provide general purpose remote I/O expansion for most
microcontroller families via the two-line bidirectional bus (I2C-bus) and is a part of the
Fast-mode Plus (Fm+) family.
The PCA9536 is an 8-pin CMOS device that provides 4 bits of General Purpose parallel
Input/Output (GPIO) expansion for I2C-bus/SMBus applications and was developed to
enhance the NXP Semiconductors family of I2C-bus I/O expanders. I/O expanders provide
a simple solution when additional I/O is needed ...
The PCA9534 is a 16-pin CMOS device that provide 8 bits of General Purpose parallel
Input/Output (GPIO) expansion for I2C-bus/SMBus applications and was developed to
enhance the NXP Semiconductors family of I2C-bus I/O expanders. The improvements
include higher drive capability, 5 V I/O tolerance, l ...
