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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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