基于单片机的多I/O节点开发设计

Design of multiple I/O nodes based on microprocessor

LonWorks推广应用的关键在于网络节点开发,以TP/FT-10F模块和AT89C2051单片机为核心设计接口电路,开发了一种通用多输入/输出智能控制节点模块。通过软件调整模拟信号采集电路的量程;应用DAC7513使放大器输出电压几乎等于电源电压;采用二极管隔离方式简化数字信号输入/输出电路;通过在电源引脚和接地引脚之间添加去耦电容,采用多层电路板布局,数字芯片的未用输入端接入高电平等方法,提高了抗电磁干扰能力;采取模拟、数字电路单元内部分别接模拟地和数字地,再将2条地线接至一点的措施,有效地降低了静态放电的影响;提出了节点故障诊断策略流程。该通用多输入/输出智能控制节点模块运行可靠。

The key of LonWorks applications is the development of network nodes. An all- purpose multi-input/output intelligent control node module -chip mieroprocessor AT89C2051 as its core. The is developed with TP/FT-10F module and single measurement range of analog signal is adjusted by software. DAC7513 is applied,the output voltage of its precise output amplifier nearly equal to power voltage. Diode isolation is applied to simplify the digital signal I/O circuts. High anti- interference capability has obtained by connecting decoupling capacitor between power pin and ground pin, adopting multi- layer printed circuit board and connecting unused inputs of digital chips to high level. Analog Ground and Digital Ground are set for internal analog and digital circuits respectively, which are then connected to one outside ground point,to greatly reduce ESD effect. Its fault diagnosis flowchart is put forward. The introduced node module runs reliably.