hi, i'm new to arduino and programing in C in general, i have experience with web programing (php, html, css, sql.).
i have bought a 8 digit, 7 segment display from DX.com and am having some troubles getting it to work. it has 2x 74HC595D's and a 5 pin connector (VCC, GND, DIO, SCK, RCK).
i have hooked it up and able to send data to it as a pair of shift register with this code:
// Pin numbers
int rck = 30;
int sck = 50;
int dio = 40;
// Binary for 0 to 9
byte num[13]={B11000000, B11111001, B10100100, B10110000, B10011001, B10010010, B10000010, B11111000, B10000000, B10011000, B10001001, B10000110, B11000111};
// Positions
byte pos[8]={1, 2, 4, 8, 16, 32, 64, 128};
void setup() {
pinMode(rck, OUTPUT);
pinMode(sck, OUTPUT);
pinMode(dio, OUTPUT);
}
void loop() {
digitalWrite(rck, LOW);
shiftOut(dio, sck, MSBFIRST, pos[0]);
shiftOut(dio, sck, MSBFIRST, num[10]);
digitalWrite(rck, HIGH);
digitalWrite(rck, LOW);
shiftOut(dio, sck, MSBFIRST, pos[1]);
shiftOut(dio, sck, MSBFIRST, num[11]);
digitalWrite(rck, HIGH);
digitalWrite(rck, LOW);
shiftOut(dio, sck, MSBFIRST, pos[2]);
shiftOut(dio, sck, MSBFIRST, num[12]);
digitalWrite(rck, HIGH);
digitalWrite(rck, LOW);
shiftOut(dio, sck, MSBFIRST, pos[3]);
shiftOut(dio, sck, MSBFIRST, num[12]);
digitalWrite(rck, HIGH);
digitalWrite(rck, LOW);
shiftOut(dio, sck, MSBFIRST, pos[4]);
shiftOut(dio, sck, MSBFIRST, num[0]);
digitalWrite(rck, HIGH);
}
and it prints "HELLO".
the problem i am having is that i am trying to use the LedControl library to simplify writing numbers to the "screen" as i want to use it as a Tachometer/temp gauge/speedometer. for an off road buggy. and am getting confusing results with the demo sketch from the LedControl library (attached is an animated gif of what i get.)
//We always have to include the library
#include "LedControl.h"
/*
Now we need a LedControl to work with.
***** These pin numbers will probably not work with your hardware *****
pin 12 is connected to the DataIn
pin 11 is connected to the CLK
pin 10 is connected to LOAD
We have only a single MAX72XX.
*/
LedControl lc=LedControl(40,50,30,2);
/* we always wait a bit between updates of the display */
unsigned long delaytime=250;
void setup() {
/*
The MAX72XX is in power-saving mode on startup,
we have to do a wakeup call
*/
lc.shutdown(0,false);
/* Set the brightness to a medium values */
lc.setIntensity(0,8);
/* and clear the display */
lc.clearDisplay(0);
}
/*
This method will display the characters for the
word "Arduino" one after the other on digit 0.
*/
void writeArduinoOn7Segment() {
lc.setChar(0,0,'a',false);
delay(delaytime);
lc.setRow(0,0,0x05);
delay(delaytime);
lc.setChar(0,0,'d',false);
delay(delaytime);
lc.setRow(0,0,0x1c);
delay(delaytime);
lc.setRow(0,0,B00010000);
delay(delaytime);
lc.setRow(0,0,0x15);
delay(delaytime);
lc.setRow(0,0,0x1D);
delay(delaytime);
lc.clearDisplay(0);
delay(delaytime);
}
/*
This method will scroll all the hexa-decimal
numbers and letters on the display. You will need at least
four 7-Segment digits. otherwise it won't really look that good.
*/
void scrollDigits() {
for(int i=0;i<13;i++) {
lc.setDigit(0,3,i,false);
lc.setDigit(0,2,i+1,false);
lc.setDigit(0,1,i+2,false);
lc.setDigit(0,0,i+3,false);
delay(delaytime);
}
lc.clearDisplay(0);
delay(delaytime);
}
void loop() {
writeArduinoOn7Segment();
scrollDigits();
}
any idea's what i'm doing wrong? as far as i can tell i am initializing LedControl correctly. LedControl(40,50,30,2);
i have tried all the combinations of the 3 pins but only this one gives anything at all. and i put the 2 as it's technically 2 shift registers instead of 1, but still only get the 1'st of the 2 4 segments to do anything.
btw, i am using a funduino mega 2560 if that is important at all.
