51 single-chip multi-machine communication system design

A bus type master is often used in a multi-machine communication system made of single chip microcomputer. In a system in which multiple microcontrollers, only one host is allowed, and the other is the slave, the slave is subject to control of the host, which is the bus type master structure. When the 51 single-chip microcomputer is multi-machine communication, the serial port is operated in the way 2 and mode 3. Assuming that the current multi-machine communication system has 1 host and 3 slave, the slave address is 00h, 01H, 02H, respectively. If the distance is very close to the TTL level, the RS-485 serial standard bus is often transmitted in terms of the distance from the distance. In order to distinguish whether data information is or address information, the host uses the ninth data TB8 as the identification bit of address / data, the TB8 = 1 of the address frame, and the TB8 = 0 of the data frame. The SM2 of each slave must be set. Before the host is communicated with a slave, the server is sent to each slave. Since each slave SM2 = 1, the received address frame RB8 = 1, the reception information of each slave is effective, and the respective receiving buffer SBUF is sent, and Ri = 1 is set. After the slave CPU response is interrupted, it is not a copy of the host by software if the host delivery is not a copy of the host, so that SM2 = 0 is maintained, otherwise SM2 = 1. The host sends a data frame, due to the ninth data RB8 = 0 of the data frame, only the slave SM2 = 0 of the address is consistent, in order to load 8-bit data into the received buffer SBUF, other slave, SM2 = 1, data Lost, there will be one-to-one communication between the host and the slave. The serial ports 2, 3 can also be used in a multi-machine communication. At this time, the ninth data can be used as a parity bit, but SM2 = 0 must be made. Source; 21IC, read full text

Our other product:

Professional lightning protection system for Tower	Professional FM Radio Station Equipment Package	FMUSER FU-1000C 1000W FM Transmitter With USB Audio Input Interface
FMUSER 200W FM Radio Broadcasting Package	Hotel IPTV Solution	FMUSER FSN-1000T V5.0 1KW FM Radio Broadcast Transmitter