485 interface chip anti-collision transceiver switching circuit device

Abstract

The invention relates to a 485 interface chip anti-collision transceiver switching circuit device, comprising: a delay circuit and a logic control circuit, the receiving output pin of the 485 interface chip is connected to the first input end of the logic control circuit through the delay circuit, The sending input pin of the 485 interface chip is connected with the second input end of the logic control circuit, and the sending enable pin and the receiving prohibition pin of the 485 interface chip are connected with the output end of the logic control circuit; The timing circuit is configured to start a delay when the level of the receiving output pin changes from the first state to the second state, and input a low level to the first input terminal of the logic control circuit within the delay time; The logic control circuit includes an inverter circuit and a NOR circuit. The patent of the invention does not depend on the situation of the conventional control chip, realizes the switching of sending and receiving data, and solves the conflict of sending and receiving, and the circuit is simple.

Description

【Technical field】 [0001] The invention relates to the technical field of communication, and more specifically relates to an anti-collision automatic transceiver switching circuit device of an interface chip for RS485 communication. 【Background technique】 [0002] RS-485 bus is a multi-node, half-duplex, differential data transmission communication method. Multiple devices can be connected to the RS-485 bus at the same time, each device has an RS485 chip, which can send and receive data, and these devices can communicate with each other through the bus. The half-duplex communication of RS485 is that the receiving and sending of data cannot be carried out at the same time. If two or more devices occupy the bus at the same time to send data, it will cause bus conflicts and cause the bus to hang. [0003] To avoid bus conflict situations, there are the following solutions: [0004] One solution is to define only one master device and multiple slave devices on the bus. The mast...

AI Technical Summary

Problems solved by technology

However, in miniaturized equipment, hardware and software resources are tight due to space costs and other reasons. For example, if there is no control chip or there is a control chip but the I / O ports are not enough, it is impossible to achieve transceiver switching and avoid bus conflicts.

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