funny characters in serial display

Projects Programming
1

hi, i have problems displaying the right text on the serial monitor, i suspect because i am using char instead of string =( not very sure, bellow is my code and serial output

void loop(void)
{

  String text ="";
  char character;
  
  gotoXY(4,4);
  {
    // wait a bit for the entire message to arrive
    delay(100);
    // clear the screen
 
    // read all the available characters
    while (Serial.available() > 0) {
     character = Serial.read();
     
     text=(&character);
    
     
  // text = String(character);
    
    // (String)character=text;
     // content.concat(character);
      // display each character to the LCD
      //gotoXY(4,4);
      
     //LcdString(text);
    Serial.println(&character);
     //LcdString(content);
      delay(100);
    }
    
      
  }

serial output

hÇ
eÇ
lÇ
lÇ
oÇ

i typed "hello" but the additional "C" like characters appear, any idea why?

thanks!!

2

You are printing the address of character not what it contains. Drop the & in both places.

3

hi! thanks for the fast reply, if i drop the &, it wouldnt compile =(

4

it would help if i posted the function for the LcdString

void LcdString(char *characters)
{
  while (*characters)
  {
    LcdCharacter(*characters++);
  }
}
5

it would help if i posted the function for the LcdString

It always helps if you post all your code to begin with, and stops people wasting their time.

So, now you see the problem?
You're sending the address of a single character to a function that expects a C string.

6

sorry, heres the full code

// The pins to use on the arduino
#define PIN_SCE   7
#define PIN_RESET 6
#define PIN_DC    5
#define PIN_SDIN  4
#define PIN_SCLK  3
 #include <sstream>
 #include <string>
// COnfiguration for the LCD
#define LCD_C     LOW
#define LCD_D     HIGH
#define LCD_CMD   0
 
// Size of the LCD
#define LCD_X     84
#define LCD_Y     48
 
int scrollPosition = -10;
 
static const byte ASCII[][5] =
{
 {0x00, 0x00, 0x00, 0x00, 0x00} // 20
,{0x00, 0x00, 0x5f, 0x00, 0x00} // 21 !
,{0x00, 0x07, 0x00, 0x07, 0x00} // 22 "
,{0x14, 0x7f, 0x14, 0x7f, 0x14} // 23 #
,{0x24, 0x2a, 0x7f, 0x2a, 0x12} // 24 $
,{0x23, 0x13, 0x08, 0x64, 0x62} // 25 %
,{0x36, 0x49, 0x55, 0x22, 0x50} // 26 &
,{0x00, 0x05, 0x03, 0x00, 0x00} // 27 '
,{0x00, 0x1c, 0x22, 0x41, 0x00} // 28 (
,{0x00, 0x41, 0x22, 0x1c, 0x00} // 29 )
,{0x14, 0x08, 0x3e, 0x08, 0x14} // 2a *
,{0x08, 0x08, 0x3e, 0x08, 0x08} // 2b +
,{0x00, 0x50, 0x30, 0x00, 0x00} // 2c ,
,{0x08, 0x08, 0x08, 0x08, 0x08} // 2d -
,{0x00, 0x60, 0x60, 0x00, 0x00} // 2e .
,{0x20, 0x10, 0x08, 0x04, 0x02} // 2f /
,{0x3e, 0x51, 0x49, 0x45, 0x3e} // 30 0
,{0x00, 0x42, 0x7f, 0x40, 0x00} // 31 1
,{0x42, 0x61, 0x51, 0x49, 0x46} // 32 2
,{0x21, 0x41, 0x45, 0x4b, 0x31} // 33 3
,{0x18, 0x14, 0x12, 0x7f, 0x10} // 34 4
,{0x27, 0x45, 0x45, 0x45, 0x39} // 35 5
,{0x3c, 0x4a, 0x49, 0x49, 0x30} // 36 6
,{0x01, 0x71, 0x09, 0x05, 0x03} // 37 7
,{0x36, 0x49, 0x49, 0x49, 0x36} // 38 8
,{0x06, 0x49, 0x49, 0x29, 0x1e} // 39 9
,{0x00, 0x36, 0x36, 0x00, 0x00} // 3a :
,{0x00, 0x56, 0x36, 0x00, 0x00} // 3b ;
,{0x08, 0x14, 0x22, 0x41, 0x00} // 3c <
,{0x14, 0x14, 0x14, 0x14, 0x14} // 3d =
,{0x00, 0x41, 0x22, 0x14, 0x08} // 3e >
,{0x02, 0x01, 0x51, 0x09, 0x06} // 3f ?
,{0x32, 0x49, 0x79, 0x41, 0x3e} // 40 @
,{0x7e, 0x11, 0x11, 0x11, 0x7e} // 41 A
,{0x7f, 0x49, 0x49, 0x49, 0x36} // 42 B
,{0x3e, 0x41, 0x41, 0x41, 0x22} // 43 C
,{0x7f, 0x41, 0x41, 0x22, 0x1c} // 44 D
,{0x7f, 0x49, 0x49, 0x49, 0x41} // 45 E
,{0x7f, 0x09, 0x09, 0x09, 0x01} // 46 F
,{0x3e, 0x41, 0x49, 0x49, 0x7a} // 47 G
,{0x7f, 0x08, 0x08, 0x08, 0x7f} // 48 H
,{0x00, 0x41, 0x7f, 0x41, 0x00} // 49 I
,{0x20, 0x40, 0x41, 0x3f, 0x01} // 4a J
,{0x7f, 0x08, 0x14, 0x22, 0x41} // 4b K
,{0x7f, 0x40, 0x40, 0x40, 0x40} // 4c L
,{0x7f, 0x02, 0x0c, 0x02, 0x7f} // 4d M
,{0x7f, 0x04, 0x08, 0x10, 0x7f} // 4e N
,{0x3e, 0x41, 0x41, 0x41, 0x3e} // 4f O
,{0x7f, 0x09, 0x09, 0x09, 0x06} // 50 P
,{0x3e, 0x41, 0x51, 0x21, 0x5e} // 51 Q
,{0x7f, 0x09, 0x19, 0x29, 0x46} // 52 R
,{0x46, 0x49, 0x49, 0x49, 0x31} // 53 S
,{0x01, 0x01, 0x7f, 0x01, 0x01} // 54 T
,{0x3f, 0x40, 0x40, 0x40, 0x3f} // 55 U
,{0x1f, 0x20, 0x40, 0x20, 0x1f} // 56 V
,{0x3f, 0x40, 0x38, 0x40, 0x3f} // 57 W
,{0x63, 0x14, 0x08, 0x14, 0x63} // 58 X
,{0x07, 0x08, 0x70, 0x08, 0x07} // 59 Y
,{0x61, 0x51, 0x49, 0x45, 0x43} // 5a Z
,{0x00, 0x7f, 0x41, 0x41, 0x00} // 5b [
,{0x02, 0x04, 0x08, 0x10, 0x20} // 5c ¥
,{0x00, 0x41, 0x41, 0x7f, 0x00} // 5d ]
,{0x04, 0x02, 0x01, 0x02, 0x04} // 5e ^
,{0x40, 0x40, 0x40, 0x40, 0x40} // 5f _
,{0x00, 0x01, 0x02, 0x04, 0x00} // 60 `
,{0x20, 0x54, 0x54, 0x54, 0x78} // 61 a
,{0x7f, 0x48, 0x44, 0x44, 0x38} // 62 b
,{0x38, 0x44, 0x44, 0x44, 0x20} // 63 c
,{0x38, 0x44, 0x44, 0x48, 0x7f} // 64 d
,{0x38, 0x54, 0x54, 0x54, 0x18} // 65 e
,{0x08, 0x7e, 0x09, 0x01, 0x02} // 66 f
,{0x0c, 0x52, 0x52, 0x52, 0x3e} // 67 g
,{0x7f, 0x08, 0x04, 0x04, 0x78} // 68 h
,{0x00, 0x44, 0x7d, 0x40, 0x00} // 69 i
,{0x20, 0x40, 0x44, 0x3d, 0x00} // 6a j
,{0x7f, 0x10, 0x28, 0x44, 0x00} // 6b k
,{0x00, 0x41, 0x7f, 0x40, 0x00} // 6c l
,{0x7c, 0x04, 0x18, 0x04, 0x78} // 6d m
,{0x7c, 0x08, 0x04, 0x04, 0x78} // 6e n
,{0x38, 0x44, 0x44, 0x44, 0x38} // 6f o
,{0x7c, 0x14, 0x14, 0x14, 0x08} // 70 p
,{0x08, 0x14, 0x14, 0x18, 0x7c} // 71 q
,{0x7c, 0x08, 0x04, 0x04, 0x08} // 72 r
,{0x48, 0x54, 0x54, 0x54, 0x20} // 73 s
,{0x04, 0x3f, 0x44, 0x40, 0x20} // 74 t
,{0x3c, 0x40, 0x40, 0x20, 0x7c} // 75 u
,{0x1c, 0x20, 0x40, 0x20, 0x1c} // 76 v
,{0x3c, 0x40, 0x30, 0x40, 0x3c} // 77 w
,{0x44, 0x28, 0x10, 0x28, 0x44} // 78 x
,{0x0c, 0x50, 0x50, 0x50, 0x3c} // 79 y
,{0x44, 0x64, 0x54, 0x4c, 0x44} // 7a z
,{0x00, 0x08, 0x36, 0x41, 0x00} // 7b {
,{0x00, 0x00, 0x7f, 0x00, 0x00} // 7c |
,{0x00, 0x41, 0x36, 0x08, 0x00} // 7d }
,{0x10, 0x08, 0x08, 0x10, 0x08} // 7e ?
,{0x00, 0x06, 0x09, 0x09, 0x06} // 7f ?
};
 
void LcdCharacter(char character)
{
  LcdWrite(LCD_D, 0x00);
  for (int index = 0; index < 5; index++)
  {
    LcdWrite(LCD_D, ASCII[character - 0x20][index]);
  }
  LcdWrite(LCD_D, 0x00);
}
 
void LcdClear(void)
{
  for (int index = 0; index < LCD_X * LCD_Y / 8; index++)
  {
    LcdWrite(LCD_D, 0x00);
  }
}
 
void LcdInitialise(void)
{
  pinMode(PIN_SCE,   OUTPUT);
  pinMode(PIN_RESET, OUTPUT);
  pinMode(PIN_DC,    OUTPUT);
  pinMode(PIN_SDIN,  OUTPUT);
  pinMode(PIN_SCLK,  OUTPUT);
 
  digitalWrite(PIN_RESET, LOW);
  digitalWrite(PIN_RESET, HIGH);
 
  LcdWrite(LCD_CMD, 0x21);  // LCD Extended Commands.
  LcdWrite(LCD_CMD, 0xBf);  // Set LCD Vop (Contrast). //B1
  LcdWrite(LCD_CMD, 0x04);  // Set Temp coefficent. //0x04
  LcdWrite(LCD_CMD, 0x14);  // LCD bias mode 1:48. //0x13
  LcdWrite(LCD_CMD, 0x0C);  // LCD in normal mode. 0x0d for inverse
  LcdWrite(LCD_C, 0x20);
  LcdWrite(LCD_C, 0x0C);
}
 
void LcdString(char *characters)
{
  while (*characters)
  {
    LcdCharacter(*characters++);
  }
}
 
void LcdWrite(byte dc, byte data)
{
  digitalWrite(PIN_DC, dc);
  digitalWrite(PIN_SCE, LOW);
  shiftOut(PIN_SDIN, PIN_SCLK, MSBFIRST, data);
  digitalWrite(PIN_SCE, HIGH);
}
 
/**
 * gotoXY routine to position cursor
 * x - range: 0 to 84
 * y - range: 0 to 5
 */
void gotoXY(int x, int y)
{
  LcdWrite( 0, 0x80 | x);  // Column.
  LcdWrite( 0, 0x40 | y);  // Row.
}
 
void drawBox(void)
{
  int j;
  for(j = 0; j < 84; j++) // top
  {
    gotoXY(j, 0);
    LcdWrite(1, 0x01);
  }
 
  for(j = 0; j < 84; j++) //Bottom
  {
    gotoXY(j, 5);
    LcdWrite(1, 0x80);
  }
 
  for(j = 0; j < 6; j++) // Right
  {
    gotoXY(83, j);
    LcdWrite(1, 0xff);
  }
 
  for(j = 0; j < 6; j++) // Left
  {
    gotoXY(0, j);
    LcdWrite(1, 0xff);
  }
}
 
void Scroll(String message)
{
  for (int i = scrollPosition; i < scrollPosition + 11; i++)
  {
    if ((i >= message.length()) || (i < 0))
    {
      LcdCharacter(' ');
    }
    else
    {
      LcdCharacter(message.charAt(i));
    }
  }
  scrollPosition++;
  if ((scrollPosition >= message.length()) && (scrollPosition > 0))
  {
    scrollPosition = -10;
  }
}
 
void setup(void)
{
  Serial.begin(115200);
  LcdInitialise();
  LcdClear();
  drawBox();
 
  gotoXY(7,1);
  //LcdString("hello");
  gotoXY(4,2);
  //LcdString("world");
}
 
void loop(void)
{

  String text ="";
  char character;
  
  gotoXY(4,1);
  {
    // wait a bit for the entire message to arrive
    delay(100);
    // clear the screen
 
    // read all the available characters
    while (Serial.available() > 0) {
     character = Serial.read();
     
     //text=(&character);

      //text.concat(character);
     // text = String(character);
      // display each character to the LCD
      //gotoXY(4,4);
      
     LcdString(character); // not able to compile
    
     
      delay(10);
    }
    
      
  }
  
  
 
}

You're sending the address of a single character to a function that expects a C string.

yes, but how do i give it a string? i have been trying to convert, but nothing works

void LcdString(char *characters)

doesn't this expects a char?
thanks

7

doesn't this expects a char?

No, it expects a C style null terminated string.
Note, not a String.

8

hi, so i tried adding a

while(character!= '\0')

but nothing has changed, is this the null terminating char u are referring to?

9

so i tried adding a

To what?
Where?
Why?

10

well, i just added a

while(character!= '\0'){
 LcdString(&character)
}

from my understanding, null terminating char is the backslash 0.... thats all i know for now

11

But you haven't added a null terminator, so testing for one is pretty pointless.

12

thanks Awol for the tips, works fine now =)

ch8eers