one , Dynamic display principle of digital tube

The feature of dynamic display is that all segments of digital tube are connected in parallel , Which digital tube is effective controlled by bit line selection
. The digital light tube adopts dynamic scanning display , The so-called dynamic scanning display is that the wheel flows to each digital tube to send out the font code and the corresponding position selection , Using the afterglow of LED and the persistence of human vision , It makes people feel as if all the digital tubes are showing at the same time
. The brightness of dynamic display is worse than that of static display , Therefore, when selecting the resistance limit, it should be slightly smaller than that in the static display circuit .

1..1, The common Yin and Yang of digital tube

Digital display of nixie tube / Nixie tube number

dp

g

f

e

d

c

b

a

0

Exterminate

Exterminate

bright

bright

bright

bright

bright

bright

1

Exterminate

Exterminate

Exterminate

Exterminate

Exterminate

bright

bright

Exterminate

2

Exterminate

bright

Exterminate

bright

bright

Exterminate

bright

bright

3

Exterminate

bright

Exterminate

Exterminate

bright

bright

bright

bright

4

Exterminate

bright

bright

Exterminate

Exterminate

bright

bright

Exterminate

5

Exterminate

bright

bright

Exterminate

bright

bright

Exterminate

bright

6

Exterminate

bright

bright

bright

bright

bright

Exterminate

bright

7

Exterminate

Exterminate

Exterminate

Exterminate

Exterminate

bright

bright

bright

8

Exterminate

bright

bright

bright

bright

bright

bright

bright

9

Exterminate

bright

bright

Exterminate

bright

bright

bright

bright

 

Common cathode digital tube

Reverse to common anode digital tube

digital display

Binary

hexadecimal

Binary

hexadecimal

0

00111111

0x3F

11000000

0xC0

1

00000110

0x06

11111001

0xF9

2

01011011

0x5B

10100100

0xA4

3

01001111

0x4F

10110000

0xB0

4

01100110

0x66

10011001

0x99

5

01101101

0x6C

10010010

0x92

6

01111101

0x9B

10000010

0x82

7

00000111

0x07

11111000

0xF8

8

01111111

0x7F

10000000

0x80

9

01101111

0x6F

10010000

0x90

       

          a         b      c         d            e          f

Common Yin a~f:  0x77  0x7c  0x39    0x5e     0x79      0x71

Gongyang a~f:  0x88  0x83  0xa7   0xa1      0x86       0x8e

two , double P Channel enhanced MOS---D74HC245 chip

characteristic :D74HC245 It's a three state output , Eight channel signal transceiver , Mainly used in large screen display , And other consumer electronics products .

 

2.1, Main characteristics

* use CMOS technology
* Wide voltage range :3.0V ---- 5V
* Bidirectional three state output
* Eight wire bidirectional transceiver
* Packaging form :SOP20,SOP20-2,TSSOP20,DIP20,
Transparent : The input is high , The output is also high ; The input is low , The output is also low ;

Two way three state

two-way : Can output , It can also be output

Three states :

* P0 High resistance output
* The pin can output high level , It can also output low level
2.2, application area

Suitable for driving display and other digital circuits .

2.3, Description of pin definition

 

Symbol

Pin name

Pin number

explain

A0 --- A7

data input / output

2 ---- 9

 

B0 ---- B7

data input / output

18 ----11

 

——

OE

 

Output enable

19

 

DIR

Direction control

1

DIR=1,A——    B,

B  ——   A

GND

Logically

20

Logically

VDD

Logic power supply

10

Power terminal

 

 

 

 

 

 

three , Function truth table

Output enable

Output control

working condition

 

——

OE  ( Low level active )

DIR

L

L

Bn input ,An output

L

H

An input ,Bn output

H

X( Output direction DIR Is any value )

High resistance state

 

four , decoder ----D74HC138

It's a three channel input , Eight channel output decoder , Mainly used in consumer electronics .

 

 

* use COMS technology
* low power consumption
* working voltage 3.0V ----5.0V
* Packaging form :SOP16
4.1, application area

It can be used in digital circuit 3—8 Decoding function

4.2, Pin description

 

4.3, Packaging form

SOP16

 

code

5.1,16 Base system

hexadecimal ( Short for hex Or subscript 16) In mathematics, it's a way of thinking 16 enter 1 The carry system of Chinese characters . Numbers are generally used 0 reach 9 And letters A reach F
( or a~f) express , among :A~F express 10~15, These are called hexadecimal numbers .

0x Hexadecimal count followed , For hexadecimal counting a~f Indicates that the bit takes a hundred value 10~15

0x3f

The hexadecimal Radix is 1, high position = Low position *16, So degree 3 The corresponding bit cardinality is 16*1=16,f The corresponding cardinality is 1, Included in 3 individual 16 and 15 individual 1, Add up to 63.

0xfc Indicates that the corresponding cardinality is 16 Here's the winner 15, The corresponding cardinality is 1 Bit value of 12, Namely 15 individual 16 plus 12 individual 1 This is a decimal number

 

 

5.2,ASCII code

 

 

5.3, Static nixie tube code
#include "reg52.h" #include "intrins.h" typedef unsigned char u8; typedef
unsigned int u16; u8 code smgduan[16] =
{0X3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f,
                                           0x77,0x7c,0x39,0x5e,0x79,0x71}; //
void main(){ P0=~smgduan[0]; while(1) { } }
5.4, Dynamic nixie tube code
#include <reg52.h> #include<intrins.h> typedef unsigned char u8; // Preprocessing data type
typedef unsigned int u16; // Preprocessing data type // 138 Definition of decoder pin sbit LSA = P2^2; sbit LSB =
P2^3; sbit LSC = P2^4; // Delay function void delay(u16 i){ while(i--); } // array
/********************************** Digital tube display truth table Gongyang 0 1 2 3 4 5 0xc0 0xf9 0xa4 0xb0
0x99 0x92 6 7 8 9 a b 0x82 0xf8 0x80 0x90 0x88 0x83 c d e f 0xa7 0xa1 0x86 0x8e
************************************* The truth table of digital display */ u8 code
smgduan[16]={0X3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f,
0x77,0x7c,0x39,0x5e,0x79,0x71}; // Common Yin void DigDisplay(){ u8 i; //
for(i=0;i<8;i++){ switch(i){ case(0): LSA = 0;LSB=0;LSC=0;break; case(1): LSA =
1;LSB=0;LSC=0;break; case(2): LSA = 0;LSB=1;LSC=0;break; case(3): LSA =
1;LSB=1;LSC=0;break; case(4): LSA = 0;LSB=0;LSC=1;break; case(5): LSA =
1;LSB=0;LSC=1;break; case(6): LSA = 0;LSB=1;LSC=1;break; case(7): LSA =
1;LSB=1;LSC=1;break; } P0 = smgduan[i]; delay(100); //P0= 0X00; } } void
main(){ P0=~smgduan[0]; while(1){ DigDisplay(); } }
 

 

six , report errors

*** WARNING L16: UNCALLED SEGMENT, IGNORED FOR OVERLAY PROCESS

    SEGMENT: ?PR?DIGDISPLAY?MAIN

The defined function was not called

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