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hansknec
Joined: 30 Sep 2004
Posts: 25
Location: Virginia, USA
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| LCD Bargraph |
 Posted: Thu May 19, 2005 1:06 pm |
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As a user that has been transitioning from PicBasicPro to PIC C, I was surprised to find that there were no canned LCD bargraph routines. (PBP didn't have one either, but the coding was commonly shared) Last year I finalized this code with the help of other users on this and other forums, but forgot to post it. The first file is LCD_bargraph.c and is fully commented. The routine works quite well, but I welcome suggestions for improvements.
| Code: |
/***LCD_bargraph.c************************************************************
Purpose: An enhancement to the standard capabilities of LCD.c that enables
one to pass a value to be bargraphed on a LCD.
Prerequisites: Must also include LCD.c in main program or add this code
to your own copy of LCD.c
//****************************************************************************
* void init_user_chars
* Purpose: Set pointer in LCD memory to CGRAM and load first 8 bytes with
* user defined characters. This function must be called once before
* a bargraph is implemented. At exit it resets pointer to line 1,
*/
void init_user_chars(void) {
// User defined characters are 5 x 7 but remember the cursor on 8
int8 i; //counting variable
// ** setup an array of special characters to form the bars ****
// char 0x00 left vertical line of bar
const char user_char[24] = {0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x00,
// char 0x01 two units of bar
0x14, 0x14, 0x14, 0x14, 0x14, 0x14, 0x14, 0x00,
// char 0x02 three units of bar (full bar)
0x15, 0x15, 0x15, 0x15, 0x15, 0x15, 0x15, 0x00};
lcd_send_byte(0,64); // Sets ram address to beginning of CGRAM area
for (i=0; i<24;i++) // fill in CGRAM with the data from array above.
lcd_send_byte(1,user_char[i]);
lcd_gotoxy(1,1); // Resets address to top line / position 1
}
/******************************************************************************
* void bargraph(int8 percent)
* Purpose: This function generates the bar graph indicator.
* Written for a 2 X 16 Intelligent LCD Display with HD44780 type controller.
* It expects a 0 to 48 value input to generate 0 to full width bar.
* B_Wdth could be modified for larger LCD's.
*/
void bargraph(BYTE percent) {
//' ** Declare Variables **
int16 Bar_Val; // Value to be graphed.
int Bars; // Number of full ||| bars to draw.
int Balance; // Balance left after all |||s are drawn.
int i; // counting variable
//' ** Declare Constants **
int const B_Wdth = 16; // Max width in characters of bar.
int const Maxbar = B_Wdth * 3; // Max bar counts.
// meat of code **
Bars = percent/3; // how many full bars to print?
Balance = percent%3; // are partial bars required?
lcd_gotoxy(1,2); // go to beginning of line 2
for (i=0; i<Bars;i++)
lcd_send_byte(1,0x02); // print the bars
switch (Balance) {
case 0: break;
case 1: lcd_send_byte(1, 0x00);
break;
case 2: lcd_send_byte(1, 0x01);
break; }
}
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The second file is a simple sample of a PIC16F877 running the code and displaying its ADC value to the LCD.
Enjoy...
| Code: |
/* bargraph_test.c *******************************************************
Authors: John Hansknecht and Daniel Charles
Purpose: This program demonstrates the use of the LCD_bargraph.c in a real
application. A PIC16F877 is set up to write to a 2X16 LCD and read
an incoming voltage on an ADC input pin. The ADC value is written
on the top line and the bottom line displays it in bargraph mode.
*/
#include <16F877.h>
#device adc=10
#fuses HS,NOWDT,NOPROTECT,NOLVP
#use delay(clock=4000000)
#include <LCD.c>
//#include <LABX1LCD.C> // Our own special file with a different port pinout
#include <LCD_bargraph.c>
long value;
int A;
void main() {
setup_adc_ports(RA0_ANALOG);
setup_adc(ADC_CLOCK_INTERNAL);
lcd_init();
delay_ms(2000);
init_user_chars(); // loads special characters into LCD CGRAM for bargraph
set_adc_channel(0);
delay_us(10);
while(1)
{
value=read_adc(); //read the ADC
delay_ms(20); //pause so we don't blur the LCD display
A=value/21; //calculate the full scale for our bar
lcd_putc('\f'); //clear the LCD
printf(lcd_putc, "value = %lu \n",value); //Print top line with ADC value
bargraph(A); //print line 2 with the bargraph output.
}
}
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jruibarroso
Joined: 07 Jan 2006
Posts: 64
Location: Braga
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| Posted: Sat Jan 21, 2006 6:10 am |
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I used this code and I had one problem:
Each time I power up the pic the display shows a diferent symbol for the bargraph. Do you know why this happens ? Thank you. |
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picmicroman
Joined: 21 Jan 2006
Posts: 1
Location: USA
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| Posted: Sun Jan 22, 2006 12:01 am |
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Hi
Thanks for the great code in deed. I have not tried yet, I need to know if its possible to use this code with HD44780 LCDs and LCD.C file,
Thanks |
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jruibarroso
Joined: 07 Jan 2006
Posts: 64
Location: Braga
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| Posted: Sun Jan 22, 2006 3:49 am |
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| i used with HD44780 LCDs and LCD.C and works fine for me !!! Thank you |
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jruibarroso
Joined: 07 Jan 2006
Posts: 64
Location: Braga
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| Posted: Sun Jan 22, 2006 3:51 am |
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i ask you hansknec if you can give me some clues how can i have a array of some graphics made by me, and print then during the program on LCD
Ex.:
printf(lcd_putc, "Some text\n");
lcd_gotoxy(1,2);
printf(lcd_putc, mygraphic[x] );
Thank you ALL !! |
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akokyaw
Joined: 11 Feb 2005
Posts: 24
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| Modification of bargraph |
| Posted: Fri Jun 02, 2006 9:53 am |
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Hi,
I have modified the bargraph that posted by hansknec. The code will clear first bar of every character while value of bar is down, as follows:
| Code: | /***LCD_bargraph.c************************************************************
Purpose: An enhancement to the standard capabilities of LCD.c that enables
one to pass a value to be bargraphed on a LCD.
Prerequisites: Must also include LCD.c in main program or add this code
to your own copy of LCD.c
//****************************************************************************
* void init_user_chars
* Purpose: Set pointer in LCD memory to CGRAM and load first 8 bytes with
* user defined characters. This function must be called once before
* a bargraph is implemented. At exit it resets pointer to line 1,
*/
void init_user_chars(void) {
// User defined characters are 5 x 7 but remember the cursor on 8
int8 i; //counting variable
// ** setup an array of special characters to form the bars ****
// char 0x00 no bar
const char user_char[32] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
// char 0x01 left vertical line of bar
0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x00,
// char 0x02 two units of bar
0x14, 0x14, 0x14, 0x14, 0x14, 0x14, 0x14, 0x00,
// char 0x03 three units of bar (full bar)
0x15, 0x15, 0x15, 0x15, 0x15, 0x15, 0x15, 0x00};
lcd_send_byte(0,64); // Sets ram address to beginning of CGRAM area
for (i=0; i<32;i++) // fill in CGRAM with the data from array above.
lcd_send_byte(1,user_char[i]);
lcd_gotoxy(1,1); // Resets address to top line / position 1
}
/******************************************************************************
* void bargraph(int8 percent)
* Purpose: This function generates the bar graph indicator.
* Written for a 2 X 16 Intelligent LCD Display with HD44780 type controller.
* It expects a 0 to 48 value input to generate 0 to full width bar.
* B_Wdth could be modified for larger LCD's.
*/
void bargraph(BYTE percent) {
//' ** Declare Variables **
int16 Bar_Val; // Value to be graphed.
int Bars; // Number of full ||| bars to draw.
int Balance; // Balance left after all |||s are drawn.
int i; // counting variable
//' ** Declare Constants **
int const B_Wdth = 40; // Max width in characters of bar.
int const Maxbar = B_Wdth * 3; // Max bar counts.
// meat of code **
Bars = percent/3; // how many full bars to print?
Balance = percent%3; // are partial bars required?
lcd_gotoxy(1,2); // go to beginning of line 4
for (i=0; i<Bars;i++)
lcd_send_byte(1,0x03); // print the bars
switch (Balance) {
case 0: lcd_send_byte(1, 0x00);
break;
case 1: lcd_send_byte(1, 0x01);
break;
case 2: lcd_send_byte(1, 0x02);
break; }
}
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Thank you, hansknec
ako |
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Mircea
Joined: 12 Jan 2007
Posts: 7
Location: Europe
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| Posted: Fri Jan 12, 2007 4:33 am |
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I think the switch statement can be replaced with only one statement.
| Code: | switch (Balance)
{
case 0: lcd_send_byte(1, 0x00); break;
case 1: lcd_send_byte(1, 0x01); break;
case 2: lcd_send_byte(1, 0x02); break;
} |
can be replaced with
| Code: | | lcd_send_byte(1, Balance); |
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tavioman
Joined: 22 Feb 2006
Posts: 65
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| Posted: Thu Mar 15, 2007 12:27 pm |
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| Mircea wrote: | I think the switch statement can be replaced with only one statement.
| Code: | switch (Balance)
{
case 0: lcd_send_byte(1, 0x00); break;
case 1: lcd_send_byte(1, 0x01); break;
case 2: lcd_send_byte(1, 0x02); break;
} |
can be replaced with
| Code: | | lcd_send_byte(1, Balance); |
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Actually the switch statement it's very useful, but without the first case. In a 4 x 20 LCD the first case causes the first character on the following logic line of the LCD to be erased. Not a very cool thing.  .
| Code: | switch (Balance)
{
//case 0: lcd_send_byte(1, 0x00); break;
case 1: lcd_send_byte(1, 0x01); break;
case 2: lcd_send_byte(1, 0x02); break;
} |
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Mircea
Joined: 12 Jan 2007
Posts: 7
Location: Europe
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| Posted: Tue May 15, 2007 7:19 am |
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tavioman,
why do you think the switch statement cannot be replace with that single statement? |
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tavioman
Joined: 22 Feb 2006
Posts: 65
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| Posted: Tue May 15, 2007 7:25 am |
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I have explained above.
Tried with the single statement or with the three cases scenario and when the cursor it's at the last position of a line the "0" case it's totally unuseful.
The cursor will jump at the next address( following line ).
I have made a software which uses three bargraphs. When in "case 0" the cursor jumped at the next line messing with my next bargraph.
Experiment and see.
The 0 case it's totally unuseful. When it's 0 I don't need to send anything to the lcd. |
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Mircea
Joined: 12 Jan 2007
Posts: 7
Location: Europe
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| Posted: Tue May 15, 2007 7:46 am |
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I thing you don't understand.
If there is a problem with the value 0 of Balance then you can use something like
| Code: | if( Balance ) lcd_send_byte(1, Balance);
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But the idea to replace an "entire" switch with a single statement remains! |
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tavioman
Joined: 22 Feb 2006
Posts: 65
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| Posted: Tue May 15, 2007 7:59 am |
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| You're right now. My main idea was that when balance is 0 we don't need to sent anything to lcd. |
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soulraven
Joined: 08 Feb 2009
Posts: 72
Location: campulung muscel
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| Posted: Tue Mar 10, 2009 4:11 am |
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| I have a problem. When the bargraph is decreased to 0, on the display remains a line from the bargraph. |
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cyrildavids
Joined: 09 May 2009
Posts: 3
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| Posted: Sat May 09, 2009 2:20 am |
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How do one make the screen display percentage instead of the numbers from 0 to 1022.
i tried making another variable that will take the Value of 'value' and divide it by the maximum number and then multiply it by 100 and every time i did run the program the only value that returns or displays on the screen is 0 for minimum or 100 for maximum.
the code is thus
| Code: | while(1)
{
value=read_adc(); //read the ADC
percent= ((value/1022)* 100);
delay_ms(20); //pause so we don't blur the LCD display
A=value/21; //calculate the full scale for our bar
lcd_putc('\f'); //clear the LCD
printf(lcd_putc, "value = %lu \n",percent); //Print top line with ADC value
bargraph(A); //print line 2 with the bargraph output.
} |
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cyrildavids
Joined: 09 May 2009
Posts: 3
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| Posted: Sat May 09, 2009 2:29 am |
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never mind i got it working
first declare the variable
| Code: | long value;
int A , percent;
float div = 10.22; |
then in the while loop
| Code: | while(1)
{
value=read_adc(); //read the ADC
percent = value/div ;
delay_ms(20); //pause so we don't blur the LCD display
A=value/21; //calculate the full scale for our bar
lcd_putc('\f'); //clear the LCD
printf(lcd_putc, "Value= %d \n",percent); //Print top line with ADC value
bargraph(A); //print line 2 with the bargraph output.
} |
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