Using a 7 segment 4 digit display with OP

AFT · Published in 2017-3-11 05:33:35

Edited by AFT at 2017-3-11 05:36

Hey Guys,

I've got a 7 segment 4 digit display (Common anode configuration), and I want to use the Orange Pi to drive it. I've got the wiringPi installed and I'm using Python.

Are there any tutorials for a beginner like me?

nopnop2002 · Published in 2017-3-12 07:18:32

Edited by nopnop2002 at 2017-3-12 07:24

It'll be as follows by a C language.
You must be change segmentDigits according to the device you use.

example for 8 segments 3 digits.

common pin : GPIO10-12
segment led pin : GPIO0-7

// 8segment anode led test
#include <stdio.h>
#include <stdlib.h>
#include <wiringPi.h>
#include <string.h>
#include <stdint.h>
#define Pins 8
#define P0 0
#define Digs 3
#define D0 10
static const uint8_t segmentDigits [] =
{
// a b c d e f g p Segments
// 0 1 2 3 4 5 6 7 wiringPi pin No.
1, 1, 1, 1, 1, 1, 0, 0, // 0
0, 1, 1, 0, 0, 0, 0, 0, // 1
1, 1, 0, 1, 1, 0, 1, 0, // 2
1, 1, 1, 1, 0, 0, 1, 0, // 3
0, 1, 1, 0, 0, 1, 1, 0, // 4
1, 0, 1, 1, 0, 1, 1, 0, // 5
1, 0, 1, 1, 1, 1, 1, 0, // 6
1, 1, 1, 0, 0, 0, 0, 0, // 7
1, 1, 1, 1, 1, 1, 1, 0, // 8
1, 1, 1, 1, 0, 1, 1, 0, // 9
1, 1, 1, 0, 1, 1, 1, 0, // A
0, 0, 1, 1, 1, 1, 1, 0, // b
1, 0, 0, 1, 1, 1, 0, 0, // C
0, 1, 1, 1, 1, 0, 1, 0, // d
1, 0, 0, 1, 1, 1, 1, 0, // E
1, 0, 0, 0, 1, 1, 1, 0, // F
0, 0, 0, 0, 0, 0, 0, 0, // blank
} ;
DisplayDigits (char* digits)
{
int i;
uint8_t digit, segment ;
uint8_t index, d, segVal ;
for (digit = 0 ; digit < Digs; ++digit) {
digitalWrite (D0 + digit, 1) ;
d = toupper (digits [digit]) ;
if ((d >= '0') && (d <= '9')) // Digit
index = d - '0' ;
else if ((d >= 'A') && (d <= 'F')) // Hex
index = d - 'A' + 10 ;
else
index = 16 ; // Blank
for (segment = 0 ; segment < 8 ; ++segment) {
segVal = segmentDigits [index * 8 + segment] ;
digitalWrite (segment+P0, !segVal) ;
//when add delay,you can understand how to work
// delay(1000);
delayMicroseconds (100) ;
digitalWrite (segment+P0, 1) ;
}
digitalWrite (D0 + digit, 0) ;
}
}
int main (void)
{
int i;
char digits [8] ;
if(wiringPiSetup() == -1) return 1;
for(i=0;i<Pins;i++) {
pinMode(P0+i, OUTPUT);
digitalWrite(P0+i, 0);
}
for(i=0;i<Digs;i++) {
pinMode(D0+i, OUTPUT);
digitalWrite(D0+i, 0);
}
strcpy(digits,"123");
for(i=0;i<3000;i++) DisplayDigits(digits);
strcpy(digits,"ABC");
for(i=0;i<3000;i++) DisplayDigits(digits);
for(i=0;i<Pins;i++) {
digitalWrite(P0+i, 0);
}
for(i=0;i<Digs;i++) {
digitalWrite(D0+i, 0);
}
exit;
}

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AFT · Published in 2017-3-15 00:48:14

nopnop2002 replied at 2017-3-12 07:18
It'll be as follows by a C language.
You must be change segmentDigits according to the device you us ...

Thanks, Your code worked. I found another one in python

from pyA20.gpio import gpio
from pyA20.gpio import port
from time import sleep
import time
gpio.init()
segments = (port.PA12,port.PA6,port.PA8,port.PA11,port.PC3,port.PA21,port.PC1,port.PA7)
for segment in segments:
gpio.setcfg(segment, gpio.OUTPUT)
gpio.output(segment, 1)
digits = (port.PG8,port.PC0,port.PC2,port.PA9)
for digit in digits:
gpio.setcfg(digit, gpio.OUTPUT)
gpio.output(digit, 0)
num = {' ':(1,1,1,1,1,1,1,1),
'0':(0,0,1,0,1,0,0,0),
'1':(1,1,1,0,1,0,1,1),
'2':(0,0,1,1,0,0,1,0),
'3':(1,0,1,0,0,0,1,0),
'4':(1,1,1,0,0,0,0,1),
'5':(1,0,1,0,0,1,0,0),
'6':(0,0,1,0,0,1,0,0),
'7':(1,1,1,0,1,0,0,0),
'8':(0,0,1,0,0,0,0,0),
'9':(1,0,1,0,0,0,0,0)}
try:
while True:
n = time.ctime()[11:13]+time.ctime()[14:16]
s = str(n).rjust(4)
for digit in range(4):
for loop in range(0,8):
gpio.output(segments[loop], num[s[digit]][loop])
if (int(time.ctime()[18:19])%2 == 0) and (digit == 1):
gpio.output(port.PA8, 0)
else:
gpio.output(port.PA8, 1)
gpio.output(digits[digit], 1)
time.sleep(0.005)
gpio.output(digits[digit], 0)
finally:
print("done")

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This one shows time on the screen.