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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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 Posted: Thu Jan 31, 2008 6:18 pm |
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Here is the driver that I did for the PicDem LCD board. It's based on
the CCS example driver file, Ex_92lcd.c. I don't have that board, so
I can't test this driver in hardware. But I looked at all the documentation
available, so I think it has a good chance to work.
The #define statements for the digits (DIGIT8_H, etc.) were determined
by looking at the #defines in lcdboard.inc (from the PicDem LCD sample
files) and Table 22-6 in the 18F8490 data sheet. I had to make two
#define statements for each digit in the LCD (_H and _L) because the
lcd_symbol() function has a bug in 16-bit mode in vs. 4.066. But it
works if you use 8-bit mode. That's why in the switch-case statement
you'll see two calls to lcd_symbol for each digit. Half of the segments
in each digit are done in each call.
The Digit_Map values were determined by realizing that CCS left-justifies
the digit segments in a 16-bit word, with segment 'a' being in bit 15.
As you can see below, I made a drawing of a 14-segment digit and then
added the bit numbers in place of the letter names for the segments.
This page shows what 14-segment numbers should look like (0 to 9).
See the middle drawing on this page:
http://www.altia.com/demos/libraries/infotainment/infotainment_fonts.htm
While looking at that drawing, I was able to determine what segments
to "turn on" for each digit. I wrote them down in binary format, as
shown below. Then I converted the binary values into 16-bit hex, and
put those values into the Digit_Map[] array.
This program uses INTRC_IO oscillator mode, at 8 MHz. That's because
the PicDem LCD board also does that. The values that are calculated for
the setup_lcd() statement depend upon the oscillator frequency. The
sample ASM code for the PicDem LCD board (from Microchip) calculates
the values at compile-time with several equations. I didn't want to
bother with that, so I just hard-coded the setup_lcd() value for the 8 MHz
internal oscillator.
| Code: |
#include <18F8490.h>
#fuses INTRC_IO,NOWDT,NOPROTECT
#use delay(clock=8000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7, ERRORS)
// A B C D E F G H
#define DIGIT8_H COM0+28, COM1+28, COM2+28, COM3+31, COM2+31, COM1+31, COM1+30, COM0+30
#define DIGIT8_L COM0+29, COM1+29, COM2+29, COM2+30, COM3+30, COM3+29, COM3+28, COM0+31
// I J K L M N 8DP 9X
#define DIGIT7_H COM0+24, COM1+24, COM2+24, COM3+27, COM2+27, COM1+27, COM1+26, COM0+26
#define DIGIT7_L COM0+25, COM1+25, COM2+25, COM2+26, COM3+26, COM3+25, COM3+24, COM0+27
#define DIGIT6_H COM0+20, COM1+20, COM2+20, COM3+23, COM2+23, COM1+23, COM1+22, COM0+22
#define DIGIT6_L COM0+21, COM1+21, COM2+21, COM2+22, COM3+22, COM3+21, COM3+20, COM0+23
#define DIGIT5_H COM0+16, COM1+16, COM2+16, COM3+19, COM2+19, COM1+19, COM1+18, COM0+18
#define DIGIT5_L COM0+17, COM1+17, COM2+17, COM2+18, COM3+18, COM3+17, COM3+16, COM0+19
#define DIGIT4_H COM0+12, COM1+12, COM2+12, COM3+15, COM2+15, COM1+15, COM1+14, COM0+14
#define DIGIT4_L COM0+13, COM1+13, COM2+13, COM2+14, COM3+14, COM3+13, COM3+12, COM0+15
#define DIGIT3_H COM0 +8, COM1 +8, COM2 +8, COM3+11, COM2+11, COM1+11, COM1+10, COM0+10
#define DIGIT3_L COM0 +9, COM1 +9, COM2 +9, COM2+10, COM3+10, COM3 +9, COM3 +8, COM0+11
#define DIGIT2_H COM0 +4, COM1 +4, COM2 +4, COM3 +7, COM2 +7, COM1 +7, COM1 +6, COM0 +6
#define DIGIT2_L COM0 +5, COM1 +5, COM2 +5, COM2 +6, COM3 +6, COM3 +5, COM3 +4, COM0 +7
#define DIGIT1_H COM0 +0, COM1 +0, COM2 +0, COM3 +3, COM2 +3, COM1 +3, COM1 +2, COM0 +2
#define DIGIT1_L COM0 +1, COM1 +1, COM2 +1, COM2 +2, COM3 +2, COM3 +1, COM3 +0, COM0 +3
// Digit numbers:
// 8 7 6 5 4 3 2 1
// ----- ----- ----- ----- ----- ----- ----- -----
// |\|/| |\|/| |\|/| |\|/| |\|/| |\|/| |\|/| |\|/|
// -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
// |/|\| |/|\| |/|\| |/|\| |/|\| |/|\| |/|\| |/|\|
// ----- ----- ----- ----- ----- ----- ----- -----
//
// Segment Segment bit
// letters: numbers:
//
// a 15
// ------- -------
// |\ i| /| |\ 7| /|
// f| \ | / |b 10| \ | / |14
// | h\|/j | | 8\|/6 |
// g--- ---k 9--- ---5
// | l/|\n | | 4/|\2 |
// e| / | \ |c 11| / | \ |13
// |/ m| \| |/ 3| \|
// ------- -------
// d 12
//
// Segment bit numbers: Segment
// 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 hex code:
// 0 1 1 1 1 1 1 - - - 1 - 1 - - - - 0xFC50
// 1 - 1 1 - - - - - - - - - - - - - 0x6000
// 2 1 1 - 1 1 - 1 - - - 1 - - - - - 0xDA20
// 3 1 1 1 1 - - 1 - - - 1 - - - - - 0xF220
// 4 - 1 1 - - 1 1 - - - 1 - - - - - 0x6620
// 5 1 - 1 1 - 1 1 - - - 1 - - - - - 0xB620
// 6 1 - 1 1 1 1 1 - - - 1 - - - - - 0xBE20
// 7 1 1 1 - - - - - - - - - - - - - 0xE000
// 8 1 1 1 1 1 1 1 - - - 1 - - - - - 0xFE20
// 9 1 1 1 1 - 1 1 - - - 1 - - - - - 0xF620
//
//
int16 const Digit_Map[10] =
{0xFC50,0x6000,0xDA20,0xF220,0x6620,0xB620,0xBE20,0xE000,0xFE20,0xF620};
// 0 1 2 3 4 5 6 7 8 9
#define BLANK 0 // For a blank digit, don't turn on any segments.
int8 lcd_pos = 0;
//-----------------------------------------------
void lcd_putc(char c)
{
int16 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: // Digit on left side of LCD.
lcd_symbol(segments >> 8, DIGIT8_H);
lcd_symbol(segments, DIGIT8_L);
break;
case 2:
lcd_symbol(segments >> 8, DIGIT7_H);
lcd_symbol(segments, DIGIT7_L);
break;
case 3:
lcd_symbol(segments >> 8, DIGIT6_H);
lcd_symbol(segments, DIGIT6_L);
break;
case 4:
lcd_symbol(segments >> 8, DIGIT5_H);
lcd_symbol(segments, DIGIT5_L);
break;
case 5:
lcd_symbol(segments >> 8, DIGIT4_H);
lcd_symbol(segments, DIGIT4_L);
break;
case 6:
lcd_symbol(segments >> 8, DIGIT3_H);
lcd_symbol(segments, DIGIT3_L);
break;
case 7:
lcd_symbol(segments >> 8, DIGIT2_H);
lcd_symbol(segments, DIGIT2_L);
break;
case 8: // Digit on right side of LCD.
lcd_symbol(segments >> 8, DIGIT1_H);
lcd_symbol(segments, DIGIT1_L);
break;
}
}
lcd_pos++;
}
//-------------------------------------------
void clear_lcd(void)
{
int16 addr;
int8 i;
addr = 0xF60; // LCDDATA0 register address
for(i=0; i < 24; i++) // Clear the LCD data registers
*addr++ = 0;
}
//==================================
void main(void)
{
int32 number;
clear_lcd();
setup_lcd(LCD_MUX14 | LCD_INTRC, 2);
number = 12345678;
printf(lcd_putc,"\f%8lu", number);
while(1);
} |
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cbarberis
Joined: 01 Oct 2003
Posts: 172
Location: Punta Gorda, Florida USA
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| Posted: Fri Feb 01, 2008 10:38 am |
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PCM programmer, I don't know how to thank you for all the time you have invested to solve and answer the above, I really appreciate this and I am sure many others like me, who first experience using the PICDEM LCD with the CCS compiler will also be thankful to you............THANK YOU  |
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cbarberis
Joined: 01 Oct 2003
Posts: 172
Location: Punta Gorda, Florida USA
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| Posted: Fri Feb 01, 2008 12:34 pm |
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| BTW I tested it on the PICDEM LCD board and it all works fine! |
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SolarGuy
Guest
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| Thanks PCM |
| Posted: Sat Mar 06, 2010 7:06 pm |
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Thanks a million for this source code for the PicDem LCD.
I have a project in which I am trying to use the LCD.
These routines work perfect with the included 18F8490.
SG |
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