HT1621 6 Digit 7 segment Display example

This is a 6-digit 7-segment LCD display module and this screen is already widely used in multimeter, electronic scales, electronic clock and ultrasonic distance measurement.

It is suitable for Ar duino motherboard and the other 5V mcu, and it has a backlight which can help you to read the screen clearly in the dark.
Features:

– Compatibility: can be directly connected to Arduino board, 51, AVR board.
– Backlight color: White
– Display Size: 1.4 inch
– Driver IC: HT1621
– Interface: 3-wire SPI
– Working Voltage: 4.7-5.2VDC
– Working Current: 0.4mA without backlight, and 4mA with backlight
– Applications: Thermometers, multimeter, electronic scales, DIY projects, etc.

5 Digit 7 segment Display

Connection

I used the following connection for the module, you can see the module pins in the image above

You can change the Arduino pins if you wish, just remember and change the defines below in the code

#define CS 2 //Pin 2 as chip selection output
#define WR 3 //Pin 3 as read clock output
#define DATA 4 //Pin 4 as Serial data output

Code

There was a lot of incomplete code examples, libraries with examples that did not work but i found this code example that requires no external libraries and worked nicely as a starting point

[codesyntax lang=”cpp”]

#define CS   2  //Pin 2 as chip selection output
#define WR   3  //Pin 3 as read clock output
#define DATA 4  //Pin 4 as Serial data output

#define CS1    digitalWrite(CS, HIGH) 
#define CS0    digitalWrite(CS, LOW)
#define WR1    digitalWrite(WR, HIGH) 
#define WR0    digitalWrite(WR, LOW)
#define DATA1  digitalWrite(DATA, HIGH) 
#define DATA0  digitalWrite(DATA, LOW)

#define sbi(x, y)  (x |= (1 << y))  
#define cbi(x, y)  (x &= ~(1 <<y ))      
#define uchar   unsigned char 
#define uint   unsigned int 

#define  ComMode    0x52  
#define  RCosc      0x30  
#define  LCD_on     0x06 
#define  LCD_off    0x04 
#define  Sys_en     0x02 
#define  CTRl_cmd   0x80
#define  Data_cmd   0xa0   


/*0,1,2,3,4,5,6,7,8,9,A,b,C,c,d,E,F,H,h,L,n,N,o,P,r,t,U,-, ,*/
const char num[]={0x7D,0x60,0x3E,0x7A,0x63,0x5B,0x5F,0x70,0x7F,0x7B,0x77,0x4F,0x1D,0x0E,0x6E,0x1F,0x17,0x67,0x47,0x0D,0x46,0x75,0x37,0x06,0x0F,0x6D,0x02,0x00,};
char dispnum[6]={0x00,0x00,0x00,0x00,0x00,0x00};


void SendBit_1621(uchar sdata,uchar cnt) 
{ 
  uchar i; 
  for(i=0;i<cnt;i++) 
  { 
    WR0;
    if(sdata&0x80) DATA1; 
    else DATA0;
    WR1;
    sdata<<=1; 
  } 
}

void SendCmd_1621(uchar command)
{ 
  CS0; 
  SendBit_1621(0x80,4);   
  SendBit_1621(command,8);
  CS1;                     
}

void Write_1621(uchar addr,uchar sdata)
{ 
  addr<<=2; 
  CS0; 
  SendBit_1621(0xa0,3);    
  SendBit_1621(addr,6);     
  SendBit_1621(sdata,8);    
  CS1; 
} 

void HT1621_all_off(uchar num)
{
  uchar i; 
  uchar addr=0; 
  for(i=0;i<num;i++) 
  { 
    Write_1621(addr,0x00); 
    addr+=2; 
  } 
}

void HT1621_all_on(uchar num)
{
  uchar i; 
  uchar addr=0; 
  for(i=0;i<num;i++) 
  {
    Write_1621(addr,0xff); 
    addr+=2; 
  } 
}

void Init_1621(void)
{
  SendCmd_1621(Sys_en);
  SendCmd_1621(RCosc);    
  SendCmd_1621(ComMode);  
  SendCmd_1621(LCD_on);
}    

void displaydata(int p)
{
  uchar i=0;
  switch(p)
  {
    case 1:
    sbi(dispnum[0],7);
    break;
    case 2:
    sbi(dispnum[1],7);
    break;
    case 3:
    sbi(dispnum[2],7);
    break;
    default:break;
  }
  for(i=0;i<=5;i++) 
  {
    Write_1621(i*2,dispnum[i]);
  }
}



void setup() {
  pinMode(CS, OUTPUT); // 
  pinMode(WR, OUTPUT); // 
  pinMode(DATA, OUTPUT); //
  CS1;
  DATA1;
  WR1;
  delay(50);
  Init_1621();
  HT1621_all_on(16); 
  delay(1000);
  HT1621_all_off(16);
  delay(1000);

  displaydata(1);//light on the first decimal point starting from the right side
  dispnum[5]=num[5];
  dispnum[4]=num[4];
  dispnum[3]=num[3];
  dispnum[2]=num[2];
  dispnum[1]=num[1];
  dispnum[0]=num[0];
  
  sbi(dispnum[5],7);  
  //cbi(dispnum[5],7);
  sbi(dispnum[4],7);   
  //cbi(dispnum[4],7); 
  sbi(dispnum[3],7);   
  //cbi(dispnum[3],7); 
  
  
  
  Write_1621(0,num[0]);  //0
  Write_1621(2,num[1]);  //1
  Write_1621(4,num[2]);  //2
  Write_1621(6,num[3]);  //3
  Write_1621(8,num[4]);  //4
  Write_1621(10,num[5]); //第5

}

void loop() {
  // put your main code here, to run repeatedly:

}

[/codesyntax]

Pretty straightforward, you should see 543210 on your display

Links

Fairly low cost for an LCD, coming in at about $5
LCD Module 2.4 inch 6-Digit 7 Segment LCD Display Module HT1621 LCD Driver IC with Decimal Point White Backlight for Arduino