51 single chip microcomputer [five] LED dot matrix screen

I will not go into details about the concepts of display resolution, pixels, and clarity.

Let's talk about the unfamiliar concept of pitch: it refers to the distance between the centers of two pixels, usually in millimeters by default. For example, p10 refers to an LED dot matrix with a pitch of 10 mm.

LED P00-P07 is directly connected to the processor, but because the processor has limited pins, the following 74HC595 is needed (the processor uses 3 pins to generate 8 parallel signals through this chip, which is equivalent to using 8 pins)

If J13 is jumpered with OE and GND, HC595 will not work. If there is no voltage, jumpered with OE and VCC, it can work.

74HC595 is a shift register. 74HC595 converts serial signals into parallel signals. P34 is the processor input serial signal, P36 is the serial clock, and P35 is the working clock. Then this chip processes and generates 8 parallel signals connected to D0-D7 of the LED matrix. 

Here this chip can also control a row of LEDs by connecting the J14 jumper cap in the figure. One end of the LED is high voltage and the other end is 8 serial high and low voltages output by HC595 to light up the LED.

void Hc595SendByte(u8 dat)

{

u8 i = 0, j = 0;

SCK = 0; // Set SCK to the initial state

RCK = 0; // Set RCK to the initial state

for (i=0; i<8; i++) //Use the for loop to send the digital signal 8 times, which is a serial signal

{

SER = dat >> 7;

dat <<= 1;

SCK = 1;

j++; // Delay code, equivalent to nop instruction

j++; // Delay code, equivalent to nop instruction

SCK = 0;

}

RCK = 1;

j++; // Delay code, equivalent to nop instruction

j++; // Delay code, equivalent to nop instruction

}

The principle of LED dot matrix display is similar to the dynamic display of digital tube

First, select each LED pixel to be lit and then refresh it repeatedly.

Link: https://pan.baidu.com/s/1-RGR0v9WUH7LWmOaUTpSbQ 

Extraction code: pmw2 

This is the font extraction software, which helps you select the LED tubes that need to be lit

Note: You need to run it as an administrator 

                  The font is generated by the CD: tool software/88 font extraction software/LEDDOT V0.2.exe

                  Note that in the menu bar settings of the mold taking software, the settings are:

                  Font display mode: single line

                  Font extraction method: column by column

                  Font extraction format: C51 format

void main(void)

{

MatrixDisplay(gZhu);

}

void MatrixDisplay(u8 *zimo)

{

u8 i = 0;

while (1)

{

for(i=0;i<8;i++)

{

MATRIX_PORT = gLineCode[i]; // bit selection

Hc595SendByte(zimo[i]); // Send segment selection data

Hc595SendByte(0x00); // Blanking

}

}

}

void Hc595SendByte(u8 dat)

{

u8 i = 0, j = 0;

SCK = 0; // Set SCK to the initial state

RCK = 0; // Set RCK to the initial state

for (i=0; i<8; i++)

{

SER = dat & (0x01);

dat >>= 1;

SCK = 1;

j++; // Delay code, equivalent to nop instruction

j++; // Delay code, equivalent to nop instruction

SCK = 0;

}

RCK = 1;

j++; // Delay code, equivalent to nop instruction

j++; // Delay code, equivalent to nop instruction

}

/*

// Since the module software can only select horizontal and vertical directions, but cannot select vertically from top to bottom or from bottom to top

// The actual test mode of the modulus software is suitable for sending LSB first instead of MSB

void Hc595SendByte(u8 dat)

{

u8 i = 0, j = 0;

SCK = 0; // Set SCK to the initial state

RCK = 0; // Set RCK to the initial state

for (i=0; i<8; i++)

{

SER = dat >> 7;

dat <<= 1;

SCK = 1;

j++; // Delay code, equivalent to nop instruction

j++; // Delay code, equivalent to nop instruction

SCK = 0;

}

The order of sending serial codes here is different from the previous one. This requires actual testing because this order may cause the actual words on the LED to be reversed.

**********************************************************************

* Header file contains

**********************************************************************

*/

#include

#include

/*

**********************************************************************

* Local macro definition

**********************************************************************

*/

typedef unsigned char u8; // Renaming type u8 simplifies code writing

typedef unsigned int u16;

#define MATRIX_PORT P0 // Dot matrix LED negative port

/*

**********************************************************************

* Local global variables

**********************************************************************

*/

sbit SCK = P3^6; // SCK rising edge shift

sbit RCK = P3^5; // RCK rising edge serial output register latch

sbit SER = P3^4; // SER pin sends byte data in

// Select the value of each element in the array. Select one column

u8 gLineCode[]={0xfe,0xfd,0xfb,0xf7,0xef,0xdf,0xbf,0x7f};  

/* Font

 * The font is generated by the CD: tool software/88 font extraction software/LEDDOT V0.2.exe

 * Note that in the menu bar settings of the mold taking software, the settings are:

 * Font display mode: single line

 * Font extraction method: column by column

 * Font extraction format: C51 format

 */

u8 gZhu[] = {0x73,0xD6,0x58,0xFF,0x58,0x54,0x52,0x12}; // Chinese character Zhu

u8 gSi[] = {0x0,0x4,0x1C,0x24,0x7E,0x4,0x0,0x0}; // number 4

u8 gK[] = {0x0,0x0,0x7E,0x38,0x66,0x0,0x0,0x0}; // Font K

/*

**********************************************************************

* Function prototype declaration

**********************************************************************

*/

void Hc595SendByte(u8 dat);

void MatrixDisplay(u8 *zimo);

/************************************************************************

* Function name: main

* Function: Main function

* Parameter list: None

* Function output: None

*************************************************************************/

void main(void)

{

MatrixDisplay(gZhu);

}

/************************************************************************

* Function name: MatrixDisplay

* Function: Refresh the font to dot matrix in a loop

* Parameter list: zimo - array of fonts to be displayed

* Function output: None

*************************************************************************/

void MatrixDisplay(u8 *zimo)

{

u8 i = 0;

while (1)

{

for(i=0;i<8;i++)

{

MATRIX_PORT = gLineCode[i]; // bit selection

Hc595SendByte(zimo[i]); // Send segment selection data

Hc595SendByte(0x00); // Blanking

}

}

}

/************************************************************************

* Function name: Hc595SendByte

* Function: Send a byte through 74HC595 serial shift

* Parameter list: dat - byte data to be sent

* Function output: None

*************************************************************************/

void Hc595SendByte(u8 dat)

{

u8 i = 0, j = 0;

SCK = 0; // Set SCK to the initial state

RCK = 0; // Set RCK to the initial state

for (i=0; i<8; i++)

{

SER = dat & (0x01);

dat >>= 1;

SCK = 1;

j++; // Delay code, equivalent to nop instruction

j++; // Delay code, equivalent to nop instruction

SCK = 0;

}

RCK = 1;

j++; // Delay code, equivalent to nop instruction

j++; // Delay code, equivalent to nop instruction

}

/*

// Since the module software can only select horizontal and vertical directions, but cannot select vertically from top to bottom or from bottom to top

// The actual test mode of the modulus software is suitable for sending LSB first instead of MSB

void Hc595SendByte(u8 dat)

{

u8 i = 0, j = 0;

SCK = 0; // Set SCK to the initial state

RCK = 0; // Set RCK to the initial state

for (i=0; i<8; i++)

{

SER = dat >> 7;

dat <<= 1;

SCK = 1;

j++; // Delay code, equivalent to nop instruction

j++; // Delay code, equivalent to nop instruction

SCK = 0;

}

RCK = 1;

j++; // Delay code, equivalent to nop instruction

j++; // Delay code, equivalent to nop instruction

}