Why this works in Arduino but not in C ?

Okada · Oct 30, 2016

Why this works in Arduino (C++) but not in C (mikroC) ?

Code:

void writeDisplay(char* msg)
{
  for (byte i=0; i < NUM_DISPLAYS; i++)
  {
    if (i < strlen(msg))
      writeMAX6955(0x25-i, msg[i]);
    else
      writeMAX6955(0x25-i, ' ');
  }
}

The strlen(msg) doesn't return string length in mikroC.

FvM · Oct 30, 2016

Without further information, it's a pretty useless post.

So far, you have written legal C code which can work in any C enviroment. But we neither know what writeMAX6955() does nor how the msg parameter is actually supplied in your program.

I feel that the below Forum rules quote describes the information content of your post quite well

Only you know what "doesn't work" means
Please tell us what your circuit or code is supposed to do and why it "doesn't work".When you come in and say "it doesn't work" or just "it has errors", that means NOTHING. There could be a million things wrong and no one will know where to look.

Okada · Oct 30, 2016

I am referring this. I have tested this in Arduino and it works. In mikroC it doesn't work.

https://timewitharduino.blogspot.in/2015/07/experimenting-with-max6955.html

FvM · Oct 30, 2016

Stlll doesn't answer the question. How have the Arduino GPIO commands in writeMAX6955() been translated to mikroC?

Okada · Oct 30, 2016

This is the mikroC PRO PIC project. I am using mikroC PRO PIC's I2C1 Library. mikroC PRO PIC project and Proteus file are attached.

It woks but in reverse. I have to make modifications to it so that data is not reverse.

This is the code.

Code C - [expand]
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#define MAX6955BaseAddress 0b11000000
 
#define reg_noOp            0x00
#define reg_decodeMode      0x01
#define reg_globalIntensity 0x02
#define reg_scanLimit       0x03
#define reg_configuration   0x04
#define reg_displayTest     0x07
#define reg_digitType       0x0C
 
#define reg_intensity10  0x10
#define reg_intensity32  0x11
#define reg_intensity54  0x12
#define reg_intensity76  0x13
#define reg_intensity10a 0x14
#define reg_intensity32a 0x15
#define reg_intensity54a 0x16
#define reg_intensity76a 0x17
 
#define USE_GLOBAL   0x00
#define USE_DISCRETE 0x40
#define RUN          0x01
#define SHUTDOWN     0x00
 
#define reg_digit0  0x60
#define reg_digit1  0x61
#define reg_digit2  0x62
#define reg_digit3  0x63
#define reg_digit4  0x64
#define reg_digit5  0x65
#define reg_digit6  0x66
#define reg_digit7  0x67
#define reg_digit0a 0x68
#define reg_digit1a 0x69
#define reg_digit2a 0x6A
#define reg_digit3a 0x6B
#define reg_digit4a 0x6C
#define reg_digit5a 0x6D
#define reg_digit6a 0x6E
#define reg_digit7a 0x6F
 
#define NUM_OF_DISPLAYS 8
 
void Delay_MilliSec(int mSec) {
     while(mSec) {
        Delay_ms(1);
        mSec--;
     }
}
 
void MAX6955_Write(unsigned char command, unsigned char data_) {
    I2C1_Start();
    I2C1_Wr(MAX6955BaseAddress);
    I2C1_Wr(command);
    I2C1_Wr(data_);
    I2C1_Stop();
    Delay_ms(5);
}
 
void MAX6955_Init() {
    I2C1_Init(100000);
    Delay_ms(200);
    
    MAX6955_Write(reg_decodeMode, 0xFF);
    MAX6955_Write(reg_scanLimit, 0x07);
    MAX6955_Write(reg_configuration, 0x01);
    MAX6955_Write(reg_globalIntensity, 0xFF);
    MAX6955_Write(reg_digitType, 0x00);
}
 
void MAX6955_Write_Display(char* msg) {
    char i;
 
    for(i = 0; i < NUM_OF_DISPLAYS; i++) {
        if(i < strlen(msg))
          MAX6955_Write((0x27 - i), msg[i]);
        else
          MAX6955_Write((0x27 - i), ' ');
    }
}
 
void MAX6955_Write_Char(char pos, char letter, char dotLit) {
    MAX6955_Write((0x27 - pos), (dotLit? 0x80 : 0) | letter);
}
 
void MAX6955_Clear() {
    char i;
    
    for(i = 0; i < NUM_OF_DISPLAYS; i++)
        MAX6955_Write((0x27 - i), ' ');
}
 
void MAX6955_Scroll_Display(char* msg, int mSec) {
    int i;
    
    for(i = 0; i <= strlen(msg); i++) {
        MAX6955_Write_Display(msg + i);
        Delay_MilliSec(mSec);
    }
}
                              
void main() {
 
    CMCON = 0x07;
 
    ADCON0 = 0x40;
    ADCON1 = 0b10001110;
    
    TRISA = 0x01;
    TRISB = 0x00;
    TRISC = 0x00;
    TRISD = 0x00;
    TRISE = 0x00;
    
    PORTA = 0x00;
    PORTB = 0x00;
    PORTC = 0x00;
    PORTD = 0x00;
    PORTE = 0x00;
 
    MAX6955_Init();
    Delay_ms(200);
 
    while(1) {
 
          MAX6955_Write_Char(0, 'A', 0);
          Delay_ms(2000);
          MAX6955_Write_Char(0, 'A', 1);
          Delay_ms(2000);
          MAX6955_Clear();
          Delay_ms(2000);
          MAX6955_Write_Display("MAXIM");
          Delay_ms(2000);
          MAX6955_Scroll_Display("Hello", 1000);
          Delay_ms(2000);
    }
}

KlausST · Oct 30, 2016

Hi,

And it doesn't answer what you expect...and what exactely does not work as expected.

What debugging have you done so far..and what are the results?

Klaus

Okada · Oct 30, 2016

I modified the code and it is working but still doesn't work if string like 234.26 is sent. Decimal point doesn't work.

And it doesn't answer what you expect...and what exactely does not work as expected.

In modified code scrolling doesn't work as needed. I need scroll display which scrolls from left to right and another right to left.

The left most display address is 0x20 and right most display address is 0x27.

I have 8 digits.

If I reduce displays to 3 digits then how should I consider the circuit ? Should I use displays with address 0x20, 0x21 and 0x22 or should I use displays with address 0x27, 0x26 and 0x25 ?

I want to make a universal library which works with any number of displays (0 to 8).

With my modified code scrolling is not working.

Florin's code prints in reverse. Maybe Florin's MAX6955 circuit is different from mine.

FvM · Oct 30, 2016

It works but in reverse. I have to make modifications to it so that data is not reverse.

That's a bit different from "not working" claimed in post #1. However you're slowly approaching reasonable problem reports.

The segment addressing seems to refer to reversed order at first sight.

Code:

MAX6955_Write((0x27 - i), msg[i]);

I'm not sure what's different in the Arduino design, may be different hardware connection?

Okada · Oct 30, 2016

That's a bit different from "not working" claimed in post #1

Actually I had done a mistake in porting the Florin's code and only Character displaying was working but string display was not working. I fixed it and it solved the problem and so the original question of this thread is solved but I have other problems.

I need a code which works for any no of displays (0 to 8). Also I need a function for scrolling from left to right and another for scrolling from right to left.

How can I implement them ?

I have not done any debugging.

Okada · Oct 30, 2016

I am still trying. Not able to some scrolling method working.

Strings like ".M.A.X" doesn't work in current scrolling methods. I have to do more thinking and make one function for sending string to MAX6955 which can be used for all kinds of scrolling like

left to right
right to left
left to right mirror
right to left mirror

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Why this works in Arduino but not in C ?

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