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aka211
Joined: 24 May 2010
Posts: 15
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| Signal noise when use LCD driver (pic16f946) ! |
 Posted: Thu Jun 17, 2010 2:52 am |
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Hi everyone,
I'm using pic16f946 and a 7-segment LCD, I config the LCD as below:
| Code: |
/////////////////////////////////////////////////////////////////////////////////////////
// LCD Configuration //
/////////////////////////////////////////////////////////////////////////////////////////
// Digit segments A B C D E F G DP
// b7 b6 b5 b4 b3 b2 b1 b0
#define DIGIT6 COM0+22, COM1+22, COM2+22, COM3+22, COM2+21, COM0+21, COM1+21
#define DIGIT5 COM0+24, COM1+24, COM2+24, COM3+24, COM2+23, COM0+23, COM1+23
#define DIGIT4 COM0+26, COM1+26, COM2+26, COM3+26, COM2+25, COM0+25, COM1+25
#define DIGIT3 COM0+33, COM1+33, COM2+33, COM3+33, COM2+27, COM0+27, COM1+27
#define DIGIT2 COM0+31, COM1+31, COM2+31, COM3+31, COM2+32, COM0+32, COM1+32
#define DIGIT1 COM0+29, COM1+29, COM2+29, COM3+29, COM2+30, COM0+30, COM1+30
// BAT RF Re. Us. V A kW h
#define SYMBOL COM3+21, COM3+23, COM3+25, COM3+27, COM3+28, COM2+28, COM1+28, COM0+28
#define COMMON COM3+32, COM3+30
#define SYMBOL2 COM0+35, COM1+35, COM2+35, COM3+35
//
// character 0 1 2 3 4 5 6 7 8 9
byte const Digit_Map[10] = {0xFC,0x60,0xDA,0xF2,0x66,0xB6,0xBE,0xE0,0xFE,0xF6};
byte const Symbol_Map[10] = {0x00,0x80,0x40,0x20,0x10,0x08,0x04,0x13,0x80,0x40};
byte const Symbol_Map2[3] = {0x00,0xc0,0xd0};
#define BLANK 0
#define DASH 11
/////////////////////////////////////////////////////////////////////////////////////////
byte lcd_pos;
void lcd_putc(char c)
{
byte segments;
if(c=='\f')
lcd_pos=0;
else
{
if((c>='0')&&(c<='9'))
segments=Digit_Map[c-'0'];
else
segments=BLANK;
switch(lcd_pos)
{ case 1 : lcd_symbol(segments,DIGIT6); break; // fill 100000s place
case 2 : lcd_symbol(segments,DIGIT5); break; // fill 10000s place
case 3 : lcd_symbol(segments,DIGIT4); break; // fill 1000s place
case 4 : lcd_symbol(segments,DIGIT3); break; // fill 100s place
case 5 : lcd_symbol(segments,DIGIT2); break; // fill 10s place
case 6 : lcd_symbol(segments,DIGIT1); break; // fill 1s place
}
}
lcd_pos++;
}
void lcd_symbol(char s)
{
byte symbols;
if((s>='0')&&(s<='7'))
{
symbols=Symbol_Map[s-'0'];
lcd_symbol(symbols,SYMBOL);
}
else symbols=BLANK;
}
void lcd_symbol2(char s2)
{
byte symbols2;
if((s2>='0')&&(s2<='2'))
{
symbols2=Symbol_Map2[s2-'0'];
lcd_symbol(symbols2,SYMBOL2);
}
else symbols2=BLANK;
}
void lcd_common(char co)
{
byte commons;
if((co=='0')||(co=='8')||(co=='9'))
{
commons=Symbol_Map[co-'0'];
lcd_symbol(commons,COMMON);
}
else commons=BLANK;
}
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But there's much noise, other ports can't be controlled.
They're all twinkling very fast and continuosly.
I just do a simple work: display a number on LCD and export a pulse to RB3 to drive a LED (active low, flash 3s). But it still don't work. LCD display OK, but LED not flash.
I use internal osc 4 Mhz.
Where's the problem, plz tell me. Thanks alot !
Here's my code :
| Code: |
#include <16F946.h>
#include <def_16f946.h>
#include <7_lcd.c>
#fuses INTRC,NOWDT,PUT
#use delay(clock=4000000)
int8 mode;
long long id1,id2;
long sym2,sym,com;
float diennang,cosphi,dienap,dongdien;
void program1();
void program2();
void program3();
void program4();
void main()
{
trisb=0x00;
rb3=1;
mode=1;
setup_oscillator( OSC_4MHZ );
setup_lcd(LCD_MUX14|LCD_STOP_ON_SLEEP,2);
dienap=220.67;
dongdien=12.328;
cosphi=1;
id1=0;
id2=12;
diennang=dienap*dongdien*cosphi;
write_eeprom(10,id2);
while(1)
{
switch(mode)
{
case 0: program1();
case 1: program2();
}
}
}
void program1()
{
sym2=2;
sym=0;
com=0;
printf(lcd_symbol2,"\f%1lu",sym2);
printf(lcd_symbol,"\f%1lu",sym);
printf(lcd_common,"\f%1lu",com);
printf(lcd_putc,"\f%06lu",id1);
rb3=0;
delay_ms(3000);
rb3=1;
delay_ms(3000);
mode=2;
}
void program2()
{
sym2=1;
sym=7;
com=8;
printf(lcd_symbol2,"\f%1lu",sym2);
printf(lcd_symbol,"\f%1lu",sym);
printf(lcd_common,"\f%1lu",com);
printf(lcd_putc,"\f%6lu",(int16)(diennang/10));
rb3=0;
delay_ms(3000);
rb3=1;
delay_ms(3000);
mode=2;
}
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Thu Jun 17, 2010 8:36 pm |
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1. Comment out all the LCD code. Does the LED now blink correctly ?
2. Did you buy the LCD board or did you build it by yourself ?
If you bought it, post a link to the webpage for the board. If you built it,
did you put ceramic 100 nF capacitors between the Vdd pins of the PIC
and ground ? Did you use a voltage regulator (7805, etc). for the +5
volts ? Did you put a 10 uF (or larger) Tantalum capacitor on the output
of the voltage regulator, from +5v to ground ?
3. What is your compiler version ? |
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aka211
Joined: 24 May 2010
Posts: 15
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| Posted: Thu Jun 17, 2010 9:35 pm |
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| PCM programmer wrote: | 1. Comment out all the LCD code. Does the LED now blink correctly ?
2. Did you buy the LCD board or did you build it by yourself ?
If you bought it, post a link to the webpage for the board. If you built it,
did you put ceramic 100 nF capacitors between the Vdd pins of the PIC
and ground ? Did you use a voltage regulator (7805, etc). for the +5
volts ? Did you put a 10 uF (or larger) Tantalum capacitor on the output
of the voltage regulator, from +5v to ground ?
3. What is your compiler version ? |
1. LED blinks as it likes, I can't control it.
2.I built it, and put 100nF ceramic capacitors between the Vdd pins of the PIC
and ground. Yes, i used 7805 for 5V. I used 100uF Tantalum capacitor on the output of the voltage regulator, from +5v to ground.
3. I use CCS_PCWHD_v4.93.
rb3 and some other pins (not used for LCD) blink continuosly at frequency of ~250Hz, VH~2V, VL~1V.
The LCD have 6 digits, 2 comons, and some symbols.
Last edited by aka211 on Thu Jun 17, 2010 9:49 pm; edited 1 time in total |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Thu Jun 17, 2010 9:46 pm |
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Try this simple test program. Compile it and run it. What happens ?
| Code: |
#include <16F946.h>
#fuses INTRC_IO, NOWDT, NOPROTECT, BROWNOUT, PUT
#use delay(clock=4000000)
//===============================
void main()
{
while(1)
{
output_high(PIN_B3);
delay_ms(500);
output_low(PIN_B3);
delay_ms(500);
}
} |
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aka211
Joined: 24 May 2010
Posts: 15
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| Posted: Thu Jun 17, 2010 9:54 pm |
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| I've tried, it works correctlly. When I don't include the "7_lcd.c", it works as i like. I think the problem is the lcd driver. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Thu Jun 17, 2010 10:06 pm |
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Do you mean that you just added the #include line for the 7_lcd.c file
as shown below, and then the program fails ?
Is the 7_lcd.c file the same as the code that you posted in an earlier post ?
| Code: |
#include <16F946.h>
#fuses INTRC_IO, NOWDT, NOPROTECT, BROWNOUT, PUT
#use delay(clock=4000000)
#include "7_lcd.c"
//===============================
void main()
{
while(1)
{
output_high(PIN_B3);
delay_ms(500);
output_low(PIN_B3);
delay_ms(500);
}
} |
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aka211
Joined: 24 May 2010
Posts: 15
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| Posted: Thu Jun 17, 2010 10:14 pm |
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When i #include <7_lcd.c> and setup_lcd(LCD_MUX14|LCD_STOP_ON_SLEEP,2);
the program fails.
| Quote: | #include <16F946.h>
#fuses INTRC_IO, NOWDT, NOPROTECT, BROWNOUT, PUT
#use delay(clock=4000000)
#include <7_lcd.c>
//===============================
void main()
{
setup_lcd(LCD_MUX14|LCD_STOP_ON_SLEEP,2);
while(1)
{
output_high(PIN_B3);
delay_ms(500);
output_low(PIN_B3);
delay_ms(500);
}
} |
Include but not setup_LCD, or setup but not include, it still works.
| Quote: | | Is the 7_lcd.c file the same as the code that you posted in an earlier post ? |
Yes, the same.
This is how it shows on oscilloscope. Yellow is COM0 pin, blue is RB3. Volts/div=2V. Time/div=5ms
 |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Thu Jun 17, 2010 10:55 pm |
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The compiler is setting bit 3 of the LCDSE0 register = '1'. This makes
pin B3 into an analog pin. That's why the LED won't work properly.
I'll continue this tomorrow. |
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aka211
Joined: 24 May 2010
Posts: 15
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| Posted: Fri Jun 18, 2010 12:11 am |
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Thanks alot PCM, so how can I config the pins not used for LCD as analog pins?
See u tomorrow,
This is my LCD:
 |
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aka211
Joined: 24 May 2010
Posts: 15
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| Posted: Fri Jun 18, 2010 2:04 am |
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I know where the problem is. It the line
setup_lcd(LCD_MUX14|LCD_STOP_ON_SLEEP,2);
I dont config the segments used for LCD ( the full syntax: setup_lcd (mode, prescale, [segments]); )
But I don't know what to write in the [segments]. In PIC16C924.h there are these defines :
| Quote: |
#define SEG0_4 1
#define SEG5_8 2
#define SEG9_11 4
#define SEG12_15 8
#define SEG16_19 16
#define SEG20_26 32
#define SEG27_28 64
#define SEG29_31 128
#define ALL_LCD_PINS 255 |
but in PIC16F946 there aren't these. So how can I define the segments correctly ? Ex, why define SEG0_4 1 ? |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Fri Jun 18, 2010 2:21 pm |
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I don't think the setup_lcd() function can handle all six bytes to control
enabling/disabling the segments in the 16F946. So as a work-around, I
wrote the following short function to load the segment registers.
Add this function above main():
| Code: |
void setup_lcd_segments(int8 se5, int8 se4, int8 se3, int8 se2, int8 se1, int8 se0)
{
#byte LCDSE0 = 0x11C
#byte LCDSE1 = 0x11D
#byte LCDSE2 = 0x11E
#byte LCDSE3 = 0x19C
#byte LCDSE4 = 0x19D
#byte LCDSE5 = 0x19E
LCDSE0 = se0;
LCDSE1 = se1;
LCDSE2 = se2;
LCDSE3 = se3;
LCDSE4 = se4;
LCDSE5 = se5;
}
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Then call the function as shown below:
| Code: |
void main()
{
setup_lcd(LCD_MUX14 | LCD_STOP_ON_SLEEP, 2);
// Enable the segments that are connected to the LCD.
// This function loads the Segment Enable registers
// with the bitmasks specified below. The segments
// are determined by looking at the schematic of the
// PIC to LCD connections. In each byte, a '1' means
// the segment is Enabled ("On"). A '0' means it's Off.
// This function must be called after the setup_lcd() function.
setup_lcd_segments(0x00, // Segs 41-40 = off
0x03, // Segs 39-34 = off, 33-32 = On
0xFF, // Segs 31-24 = On
0xE0, // Segs 23-21 = On, 20-16 = off
0x00, // Segs 15-8 = off
0x00); // Segs 7-0 = off
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Or if you didn't want to do this, you could just put in the #byte statements
and set the 6 LCDSEn registers in main() with 6 lines. But I like functions. |
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aka211
Joined: 24 May 2010
Posts: 15
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| Posted: Sat Jun 19, 2010 10:44 pm |
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Thanks PCM, I'll try. My internet line had problem so i couldn't be online these days. I'll try and tell you the result.
Best wishes, PCM |
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aka211
Joined: 24 May 2010
Posts: 15
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| Posted: Sun Jun 20, 2010 8:09 pm |
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| It's great PCM, it works well. Thank you very much. |
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