"It feels good to use a computer to control a single chip microcomputer and then control relays and other peripherals. How can it be realized? Step by step.
MCU serial port communication, that is, the communication between MCU and computer, to realize, we should understand some basic concepts.
(1) Before implementation, please make sure that the serial port is normal. I have done serial port operation before and can't control it after burning. Later, I found that there is an exclamation mark in the serial port in the device manager and there is a problem with the driver. It may be caused by the failure to plug in the development experimental board or the replacement of a USB port (I use serial port to USB, laptop)
(2) Serial port initialization, in this regard, it is best to have relevant books to understand the digestion timer and interrupt, so that the operation is easy.
One. Set the working mode of the serial port: set the scon register.
What is scon?
Scon register is an addressable special register of 51 single chip microcomputer, which is used for the control of serial data communication. Its byte address is 98H and bit address is 98H ~ 9fh. The content is:
SM0SM1SM2RENTB8RB8TIRI
SM0 SM1: serial port working mode selection bit.
Sm0sm1 working mode function baud rate
00 mode 0 8-bit synchronous shift register FOSC / 12
01 mode 1 10 bit UART variable
10 mode 2 11 bit UART FOSC / 64 (or FOSC / 32)
11 mode 3 11 bit UART variable
-----------------------------------------------------------
SM2: multi machine communication control bit
Ren: Reception permission control, 1 is to allow serial port reception, and 0 is to prohibit serial port reception.
TB8: the 9th data bit sent.
Rb8: the 9th data bit received.
Ti: send interrupt flag. After sending a frame of data, the hardware automatically sets 1. The Ti bit must be cleared by the software.
RI: receive interrupt flag. After receiving a frame of data, the hardware automatically sets 1. The RI bit must be cleared by the software.
Example: use the serial port debugging assistant to debug the serial port and send the hexadecimal number to make the corresponding LED light up.
C. The procedure is as follows:
#include
void main（）
{
TMOD=0x20; // Set timer: Timer1 mode 2 8-bit reload
TH1=0xfd; // Baud rate for 9600 baud @ 11.0592Mhz
TL1=0xfd;
SM0=0;
SM1=1;
REN=1; // Control RI to allow serial reception. Sm0sm1 and Ren are scon = 0x50;
TR1=1; // Start timer 1
while（1）
{
If (RI = = 1) / / if RI is 1, the data sent from the serial port is received
{
RI=0; / / the library software is cleared. must
P0=SBUF; // SBUF is a buffer. The receiving buffer can only read but not write, and the transmitting buffer can only write but not read.
/*They share a byte address and are independent of each other*/
}
}
}
The above are serial control LED lights. You can send which lights you want to display through serial port debugging software.
Example: nixie tube display. Only one display is given here. If there are more than one, you can add the relevant program segment yourself.
#include
void main（）
{
TMOD=0x20;
TH1=0xfd;
TL1=0xfd;
SM0=0;
SM1=1;
REN=1; // Control ri
TR1=1;
while（1）
{
if（RI==1）
{
RI=0;
P0=SBUF; // P0 is the value of nixie tube.
P2=0x06; // 8-bit nixie tube, the seventh, P2 port is chip selection,
}
}
}
The above program can be debugged and run on AT89S52 single chip microcomputer + keil.
Related tools:
Serial debugging assistant, 51 serial communication calculator. Exe, which can be searched and downloaded on the Internet., Read the full text, technical section
STM32 MCU Tim module timer up overflow output comparison
Three development directions of single chip microcomputer chip
Analysis of scon register and C program of 51 single chip microcomputer
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