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johnl
Joined: 30 Sep 2003
Posts: 120
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| LCD vs OLED with Flex_LCD.c |
 Posted: Mon Nov 22, 2021 3:13 pm |
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If the code is run with an HD44780 controlled LCD, the output is what is expected: first "XY" appears on line 2, then after one second the four lines appear.
If the same code is run with the OLED display (with the WS0010 controller), "XY" appears, then only lines 2,3 and 4 appear with line 1 blank on the display.
The same hardware is used in the test with just the module swapped. Compiler 4.128.
Here's the LCD used for the test:
https://www.datasheet.live/index.php?title=Special:PdfViewer&url=https%3A%2F%2Fpdf.datasheet.live%2F2178337d%2Fdenstron.com%2FLM4434BG4C20CBY.pdf
...and the OLED:
https://www.crystalfontz.com/product/cfal2004ay-character-oled-module
| Code: |
#include <18F4520.h>
#include <string.h>
#include <stdlib.h>
#FUSES NOBROWNOUT, WDT32
#FUSES NOWDT,NODEBUG,NOLVP,NOPROTECT,EC_IO
#FUSES NOEBTRB, NOPUT, BORV43
#use delay(clock=18452000)
#include "OLED_flex.c"
char const menu1[]="\f-------LINE 1-------
-------LINE 2-------
-------LINE 3-------
-------LINE 4-------";
void main(void)
{
set_tris_a(0b00010000);
set_tris_b(0b11110000);
set_tris_c(0b10000001);
set_tris_d(0);
set_tris_e(0);
port_b_pullups(TRUE);
lcd_init();
lcd_gotoxy(1,2);
lcd_putc("XY");
delay_ms(1000);
lcd_putc(menu1);
while(1);
}
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The driver was modified as per PCM Programmer's advice in an old post:
| Code: |
// OLED_flex.c SAME AS Flex_LCD420.c except for lines 192 and 262
// These pins are for my Microchip PicDem2-Plus board,
// which I used to test this driver.
// An external 20x4 LCD is connected to these pins.
// Change these pins to match your own board's connections.
#define LCD_DB4 PIN_D0
#define LCD_DB5 PIN_D1
#define LCD_DB6 PIN_D2
#define LCD_DB7 PIN_D3
#define LCD_RS PIN_B0
#define LCD_RW PIN_B2
#define LCD_E PIN_B1
/*
// To prove that the driver can be used with random
// pins, I also tested it with these pins:
#define LCD_DB4 PIN_D4
#define LCD_DB5 PIN_B1
#define LCD_DB6 PIN_C5
#define LCD_DB7 PIN_B5
#define LCD_RS PIN_E2
#define LCD_RW PIN_B2
#define LCD_E PIN_D6
*/
// If you want only a 6-pin interface to your LCD, then
// connect the R/W pin on the LCD to ground, and comment
// out the following line. Doing so will save one PIC
// pin, but at the cost of losing the ability to read from
// the LCD. It also makes the write time a little longer
// because a static delay must be used, instead of polling
// the LCD's busy bit. Normally a 6-pin interface is only
// used if you are running out of PIC pins, and you need
// to use as few as possible for the LCD.
#define USE_RW_PIN 1
// These are the line addresses for most 4x20 LCDs.
#define LCD_LINE_1_ADDRESS 0x00
#define LCD_LINE_2_ADDRESS 0x40
#define LCD_LINE_3_ADDRESS 0x14
#define LCD_LINE_4_ADDRESS 0x54
// These are the line addresses for LCD's which use
// the Hitachi HD66712U controller chip.
/*
#define LCD_LINE_1_ADDRESS 0x00
#define LCD_LINE_2_ADDRESS 0x20
#define LCD_LINE_3_ADDRESS 0x40
#define LCD_LINE_4_ADDRESS 0x60
*/
//========================================
#define lcd_type 2 // 0=5x7, 1=5x10, 2=2 lines(or more)
int8 lcd_line;
int8 const LCD_INIT_STRING[4] =
{
0x20 | (lcd_type << 2), // Set mode: 4-bit, 2+ lines, 5x8 dots
0xc, // Display on
1, // Clear display
6 // Increment cursor
};
//-------------------------------------
void lcd_send_nibble(int8 nibble)
{
// Note: !! converts an integer expression
// to a boolean (1 or 0).
output_bit(LCD_DB4, !!(nibble & 1));
output_bit(LCD_DB5, !!(nibble & 2));
output_bit(LCD_DB6, !!(nibble & 4));
output_bit(LCD_DB7, !!(nibble & 8));
delay_cycles(1);
output_high(LCD_E);
delay_us(2);
output_low(LCD_E);
}
//-----------------------------------
// This sub-routine is only called by lcd_read_byte().
// It's not a stand-alone routine. For example, the
// R/W signal is set high by lcd_read_byte() before
// this routine is called.
#ifdef USE_RW_PIN
int8 lcd_read_nibble(void)
{
int8 retval;
// Create bit variables so that we can easily set
// individual bits in the retval variable.
#bit retval_0 = retval.0
#bit retval_1 = retval.1
#bit retval_2 = retval.2
#bit retval_3 = retval.3
retval = 0;
output_high(LCD_E);
delay_us(1);
retval_0 = input(LCD_DB4);
retval_1 = input(LCD_DB5);
retval_2 = input(LCD_DB6);
retval_3 = input(LCD_DB7);
output_low(LCD_E);
delay_us(1);
return(retval);
}
#endif
//---------------------------------------
// Read a byte from the LCD and return it.
#ifdef USE_RW_PIN
int8 lcd_read_byte(void)
{
int8 low;
int8 high;
output_high(LCD_RW);
delay_cycles(1);
high = lcd_read_nibble();
low = lcd_read_nibble();
return( (high<<4) | low);
}
#endif
//----------------------------------------
// Send a byte to the LCD.
void lcd_send_byte(int8 address, int8 n)
{
output_low(LCD_RS);
#ifdef USE_RW_PIN
while(bit_test(lcd_read_byte(),7)) ;
#else
delay_us(60);
#endif
if(address)
output_high(LCD_RS);
else
output_low(LCD_RS);
delay_cycles(1);
#ifdef USE_RW_PIN
output_low(LCD_RW);
delay_cycles(1);
#endif
output_low(LCD_E);
lcd_send_nibble(n >> 4);
lcd_send_nibble(n & 0xf);
}
//----------------------------
void lcd_init(void)
{
int8 i;
lcd_line = 1;
output_low(LCD_RS);
#ifdef USE_RW_PIN
output_low(LCD_RW);
#endif
output_low(LCD_E);
// Some LCDs require 15 ms minimum delay after
// power-up. Others require 30 ms. I'm going
// to set it to 35 ms, so it should work with
// all of them.
delay_ms(550); ///***/// CHANGED FROM delay_ms(35);
for(i=0 ;i < 3; i++)
{
lcd_send_nibble(0x03);
delay_ms(5);
}
lcd_send_nibble(0x02);
for(i=0; i < sizeof(LCD_INIT_STRING); i++)
{
lcd_send_byte(0, LCD_INIT_STRING[i]);
// If the R/W signal is not used, then
// the busy bit can't be polled. One of
// the init commands takes longer than
// the hard-coded delay of 50 us, so in
// that case, lets just do a 5 ms delay
// after all four of them.
#ifndef USE_RW_PIN
delay_ms(5);
#endif
}
}
//----------------------------
void lcd_gotoxy(int8 x, int8 y)
{
int8 address;
switch(y)
{
case 1:
address = LCD_LINE_1_ADDRESS;
break;
case 2:
address = LCD_LINE_2_ADDRESS;
break;
case 3:
address = LCD_LINE_3_ADDRESS;
break;
case 4:
address = LCD_LINE_4_ADDRESS;
break;
default:
address = LCD_LINE_1_ADDRESS;
break;
}
address += x-1;
lcd_send_byte(0, 0x80 | address);
}
//-----------------------------
void lcd_putc(char c)
{
switch(c)
{
case '\f':
lcd_send_byte(0,1);
lcd_line = 1;
delay_ms(7); ///***/// CHANGED FROM delay_ms(2)
break;
case '\n':
lcd_gotoxy(1, ++lcd_line);
break;
case '\b':
lcd_send_byte(0,0x10);
break;
default:
lcd_send_byte(1,c);
break;
}
}
//------------------------------
#ifdef USE_RW_PIN
char lcd_getc(int8 x, int8 y)
{
char value;
lcd_gotoxy(x,y);
// Wait until busy flag is low.
while(bit_test(lcd_read_byte(),7));
output_high(LCD_RS);
value = lcd_read_byte();
output_low(LCD_RS);
return(value);
}
#endif
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temtronic
Joined: 01 Jul 2010
Posts: 9228
Location: Greensville,Ontario
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| Posted: Mon Nov 22, 2021 8:53 pm |
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Hmm, I followed the oled link and only got 2 line display, so not too sure why you'd use a driver designed for 4 line use.
Then the links for the WS device didn't give details line accessing it...
sigh... |
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johnl
Joined: 30 Sep 2003
Posts: 120
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| Posted: Mon Nov 22, 2021 9:49 pm |
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There's a 4x20 line version of the driver called Flex_LCD420.c by PCM Programmer.
The OLED display is 4x20. here's the controller chip:
http://www.crystalfontz.com/controllers/Winstar%20Display/WS0010/
The links lead me to 4 line displays. The first one is the LCD, second is the OLED.
I don't know why you saw only a 2 line display.
Thanks. |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19515
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| Posted: Tue Nov 23, 2021 2:22 am |
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Though the WS0010 is very similar, it is not the same.
The clear screen instruction does not automatically 'home' the display.
So you need to send either the home command (there is a separate home
command on this - quite easy to add this as a command), or send a goto
0,0, before the menu line.
You will find quite a few threads about this difference with the Adafruit
libraries. |
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temtronic
Joined: 01 Jul 2010
Posts: 9228
Location: Greensville,Ontario
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| Posted: Tue Nov 23, 2021 6:42 am |
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to johnl...
I just followed your new 'blue link'...got the WS0010.pdf and that 43 page document only has 1 and 2 line display info.
man I'd like to know what I'm doing wrong, I don't want to go outside , it's cold and ice on the ground... |
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johnl
Joined: 30 Sep 2003
Posts: 120
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| Posted: Tue Nov 23, 2021 12:44 pm |
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| Ttelmah wrote: | Though the WS0010 is very similar, it is not the same.
The clear screen instruction does not automatically 'home' the display.
So you need to send either the home command (there is a separate home
command on this - quite easy to add this as a command), or send a goto
0,0, before the menu line.
You will find quite a few threads about this difference with the Adafruit
libraries. |
Thanks. You're right.. it's just the way the WS0010 driver handles the \f.
I just added a gotoxy call the the \f case and that solved the problem. |
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johnl
Joined: 30 Sep 2003
Posts: 120
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| Posted: Tue Nov 23, 2021 12:47 pm |
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| temtronic wrote: | to johnl...
I just followed your new 'blue link'...got the WS0010.pdf and that 43 page document only has 1 and 2 line display info.
man I'd like to know what I'm doing wrong, I don't want to go outside , it's cold and ice on the ground... |
temtronic, It's confusing. The driver only mentions two lines, but somehow it handles 4 lines with a second chip. Anyway, for now the problem is solved. You can stay warm and safe inside! |
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