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kel
Joined: 17 Oct 2005
Posts: 68
Location: Brisbane
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| Bargraph on LCD & Pic16f877a |
 Posted: Mon Feb 20, 2006 12:20 am |
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The code on bargraph in the code library section work fine but it leaves vertical bars on the first & last last ends of the pixel.
| Code: | #include <16F877.h>
#device adc=10
#fuses HS,NOWDT,NOPROTECT,NOLVP
#use delay(clock=4000000)
#include <LCD.c>
#include <LCD_bargraph.c>
/* bargraph_test.c /***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; }
}
/* 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.
*/
long value,Temp;
int A;
void main() {
setup_adc_ports(AN0);
setup_adc(DIV_32);
lcd_init();
delay_ms(2000);
init_user_chars(); // loads special characters into LCD CGRAM for bargraph
set_adc_channel(0);
delay_us(20);
while(1)
{
value=read_adc(); //read the ADC
delay_ms(20); //pause so we don't blur the LCD display
Temp= (value-559L)/2; //Calculate the temperature in degrees
A=Temp; //calculate the full scale for our bar
lcd_putc('\f'); //clear the LCD
printf(lcd_putc, "value = %lu \n",Temp); //Print top line with ADC value
bargraph(A); //print line 2 with the bargraph output.
}
} |
For examples if temp=25oC,then 8 full bars are printed plus the remaining 1 bar.If the temperature increases the numbers printed increases. But when temperature is dropping, two vertical bars areleft at the start and end of the of a pixel i.e.
instead of a blank bar?
Anyone have any idea? coz you won't want have a bargraph that leaves some bars when values are dropping.it suppose to clear them when there are no values.
Thanks |
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jecottrell
Joined: 16 Jan 2005
Posts: 559
Location: Tucson, AZ
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| Posted: Mon Feb 20, 2006 8:18 am |
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Kel,
I'm not sure if your problem is with "remnants" left over as the value decreases or if it is a problem displaying the bar? I remember when I modified the code for a battery indicator I believe there were some missing characters. Try this:
| Code: |
/*******************************************************************************
* void generatebar(int8 percent)
* Purpose: This function generates the text line for the bar graph indicator.
This will generate a 16 character bar graph.
*/
void generate_bar(int16 percent) {
int16 solid;
int16 last;
int8 i = 0;
solid = (percent * 16) / 100; // number of solid characters to display
last = ((percent * 16) - (solid * 100)) / 10; // work out the last character
last /= 2;
if (solid) {
for (i = 0; i < solid; i++)
bar[i] = 0x05;
}
if (last) {
last--;
bar[i] = last; // select last character
i++;
}
bar[i] = 0x00; // null terminator
}
/*****************************************************************************
* init_user_chars
* Purpose: Set pointer in LCD memory to CGRAM and load first 8 bytes with
* user defined characters. Reset pointer to line 1, position 1
*/
void init_bar_graph_chars(void) {
// User defined characters 5 x 7 but remember the cursor on 8
int8 i;
const char user_char[49] = {
// char 0x00 low battery indicator
0x0E, 0x1B, 0x11, 0x11, 0x11, 0x11, 0x11, 0x1F,
// char 0x01 20% solid vertical for bar graph
0x00, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10,
// char 0x02 40% solid vertical for bar graph
0x00, 0x18, 0x18, 0x18, 0x18, 0x18, 0x18, 0x18,
// char 0x03 60% solid vertical for bar graph
0x00, 0x1C, 0x1C, 0x1C, 0x1C, 0x1C, 0x1C, 0x1C,
// char 0x04 80% solid vertical for bar graph
0x00, 0x1E, 0x1E, 0x1E, 0x1E, 0x1E, 0x1E, 0x1E,
// char 0x05 solid block for bar graph
0x00, 0x1F, 0x1F, 0x1F, 0x1F, 0x1F, 0x1F, 0x1F,
};
lcd_send_byte(0,64); // Sets ram address
for (i = 0; i < 49; i++)
lcd_send_byte(1,user_char[i]);
lcd_gotoxy(1,1); // Resets address to top line / position 1
} // init_user_chars
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kel
Joined: 17 Oct 2005
Posts: 68
Location: Brisbane
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| 16f877a bargraph problem |
| Posted: Mon Feb 20, 2006 9:29 pm |
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Indeed the problem is with "remnants" left over as the values decreases.
By the way did you define as static global? |
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tomal
Joined: 20 Nov 2011
Posts: 9
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| Posted: Thu Jul 25, 2013 11:33 am |
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I'm suffering from the same "remnants" (left over as the values decreases) issues for the bargraph.
Anybody have a workaround?
thanks |
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