οι lcd με 16 ποδάρια είναι με back light συγκεκριμένα είναι
15 V+
16 V-
ο τρόπος που την δουλεύω εγώ είναι το 16 στην γή και το 15 στο όγδοο (πιν7) ποδάρι
της πορτας του avr (τα άλλα πιν της ίδιας πόρτας απο πιν0 εώς πιν6 οδηγούν την οθόνη
σε 4 μπιτ mode)
με logic high στο 15 (pin7) θα ανάψει το back light.
ο πιο βολικός τρόπος είναι μέσω της A αν δεν χρησημοποιείς το build in adc μιας και οι άλλες πόρτες έχουν χρήσιμες λειτουργίες
ίσως και η PC σε βολέψει (σε κάποιον μC που έχει βέβεια).
Για να την λειτουργήσεις πρέπει να προσέξεις κάποια πράγματα εκτός απο τις βασικές εντολές (HOME, CLR, SHIFTS κλπ):
τους χρονισμούς στο init
Ανακεφαλαίωση:
Διαβάσεις το συνημένο που λέει τα πάντα και είναι uC independent.
Έχει τους χρονισμούς, τις εντολές για οθόνες μίας και δύο γραμμών καθώς
και 4 και 8 μπιτ mode
Συνιστώμενo wiring (avr-gcc)
// avr config definitions
#define LCD_PORT PORTA
#define LCD_PORTIN PINA
#define LCD_DDR DDRA
// 4 bit mode, data cables
#define LCD_D4 PORT0
#define LCD_D5 PORT1
#define LCD_D6 PORT2
#define LCD_D7 PORT3
// mcu control cables
#define LCD_RW PORT4
#define LCD_E PORT5
#define LCD_RS PORT6
// power on/off cable
#define LCD_PW PORT7
προσοχή στο αρχείο main.c , είναι γραμμένο για κάθε κρύσταλλο
εκτός απο την lcd_pulse_e() που ίσως χρειαστεί να κρατήσεις τον παλμό
σηκωτέο λίγο παραπάνω σε περισσότερα MHz
// pulse the enable r/w pin
static inline void lcd_pulse_e(void)
{
LCD_PORT |= 1 << LCD_E;
// with greater clock a small delay
// maybe be needed
// ie: __asm__ volatile ( "nop");
LCD_PORT &= ~(1 << LCD_E);
}
και φυσικά όλα προυποθέτουν ότι η οθόνη σου είναι hd44780 συμβατή
main.c (avr-gcc main program)
// frequency of ext crystal in Hz
// set the low fuse, low nibble as recommended for F_CPU
// using a programmer
#define F_CPU 4000000UL
#include <ctype>
#include <stdint>
#include <stdio>
#include <avr>
#include <avr>
#include <util>
#include <stdbool>
// avr config definitions
#define LCD_PORT PORTA
#define LCD_PORTIN PINA
#define LCD_DDR DDRA
// 4 bit mode, data cables
#define LCD_D4 PORT0
#define LCD_D5 PORT1
#define LCD_D6 PORT2
#define LCD_D7 PORT3
// mcu control cables
#define LCD_RW PORT4
#define LCD_E PORT5
#define LCD_RS PORT6
// power on/off cable
#define LCD_PW PORT7
// mask for data bits 0x0f
#define LCD_DATABITS ((1 << LCD_D4) | (1 << LCD_D5) | (1 << LCD_D6) | (1 << LCD_D7))
// mask of the busy flag, used as cable LCD_D7
#define LCD_BUSYFLAG 0x80
// used as functions
#define lcd_outcmd(n) lcd_outbyte((n), 0)
#define lcd_outdata(n) lcd_outbyte((n), 1)
#define lcd_incmd() lcd_inbyte(0)
#define lcd_indata() lcd_inbyte(1)
// definitions for lcd instructions
#define LCD_CLR 0x01
#define LCD_HOME 0x02
#define LCD_ENTMODE 0x04
#define LCD_DISPCTL 0x0C
#define LCD_FNSET 0x28
// pulse the enable r/w pin
static inline void lcd_pulse_e(void)
{
LCD_PORT |= 1 << LCD_E;
// delay for 500 ns
//__asm__ volatile("nop");
//__asm__ volatile("nop");
LCD_PORT &= ~(1 << LCD_E);
}
static void lcd_outnibble(uint8_t n, uint8_t rs)
{
// set in write mode
LCD_PORT &= ~(1 << LCD_RW);
// enable or disable register select
if (rs)
LCD_PORT |= 1 << LCD_RS;
else
LCD_PORT &= ~(1 <<LCD_RS>>4, rs);
// out low nibble
lcd_outnibble(b & 0x0f, rs);
}
static uint8_t lcd_innibble(uint8_t rs)
{
// set RW of lcd_port high, this is read
LCD_PORT |= 1 << LCD_RW;
// set lcd_ddr high nibble as is, low nibble to zeros
// this is input for port0 to port3
LCD_DDR &= ~LCD_DATABITS;
// enable or disable register select
if (rs)
LCD_PORT |= 1 << LCD_RS;
else
LCD_PORT &= ~(1 << LCD_RS);
// pulse_e so data transfer can start
lcd_pulse_e();
// whatever is high and it with databits
uint8_t x = LCD_PORTIN & LCD_DATABITS;
// high the databits in data direction register
// configure them again as output
LCD_DDR |= LCD_DATABITS;
// low the rw bit in lcd_port
// this brings the system in write mode
LCD_PORT &= ~(1 << LCD_RW);
// erase high nibble of x
return x & LCD_DATABITS;
}
uint8_t lcd_inbyte(uint8_t rs)
{
uint8_t x;
// read nibble and shift to the high part of x
x = lcd_innibble(rs) << 4;
// read nibble and leave it as is
x |= lcd_innibble(rs);
return x;
}
void lcd_wait_ready(void)
{
// busy wait for the compination of RS = 0 (instuction) and RW = 1 (read)
while (lcd_incmd() & LCD_BUSYFLAG)
;
}
int main(void)
{
// set data direction reg as output
LCD_DDR = (1 << LCD_RS) | (1 << LCD_RW) | (1 << LCD_E) | LCD_DATABITS;
// clean the port
// LCD_PORT = 0xf0 & LCD_DATABITS;
// delay for 15 ms with 4.5V power
_delay_ms(15);
// the low nibble of this must be 0011
lcd_outnibble(0x03, 0);
// delay for 4.1 ms
_delay_ms(4.1);
lcd_outnibble(0x03, 0);
// delay for 100 us
_delay_us(100);
// interface to be four bit long
lcd_outnibble(0x02, 0);
lcd_wait_ready();
// lines=2
lcd_outbyte(0x28, 0);
lcd_wait_ready();
// display on , cursor off
lcd_outbyte(0x0c, 0);
lcd_wait_ready();
// display clear
lcd_outbyte(0x01, 0);
lcd_wait_ready();
// entry mode set
lcd_outbyte(0x03, 0);
lcd_wait_ready();
lcd_outbyte('w', 1);
lcd_wait_ready();
lcd_outbyte('o', 1);
lcd_wait_ready();
lcd_outbyte('r', 1);
lcd_wait_ready();
lcd_outbyte('k', 1);
lcd_wait_ready();
lcd_outbyte('s', 1);
lcd_wait_ready();
lcd_outbyte('?', 1);
lcd_wait_ready();
return 0;
}
makefile for main.c
PRG= main
OBJ = main.o
TARGET = atmega16
OPTIONS = -g -Wall -Os
CC = avr-gcc
CFLAGS = $(OPTIONS) -mmcu=$(TARGET)
LDFLAGS = -Wl,-Map,$(PRG).map
OBJCOPY = avr-objcopy
OBJDUMP = avr-objdump
# avrdude
AD_PART = m16
AD_PORT = /dev/ttyS0
AD_BOARD = stk500v2
AD_CONFIG = -p $(AD_PART) -P $(AD_PORT) -c $(AD_BOARD)
AD_LOFUSE = 0xEE
AD_HIFUSE = 0xD9
all: $(PRG).elf lst text
$(PRG).elf: $(OBJ)
$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $^
lst: $(PRG).lst
%.lst: %.elf
$(OBJDUMP) -h -S $< > $@
text: hex bin srec
hex: $(PRG).hex
bin: $(PRG).bin
srec: $(PRG).srec
%.hex: %.elf
$(OBJCOPY) -j .text -j .data -O ihex $< $@
%.srec: %.elf
$(OBJCOPY) -j .text -j .data -O srec $< $@
%.bin: %.elf
$(OBJCOPY) -j .text -j .data -O binary $< $@
eeprom: ehex ebin esrec
ehex: $(PRG)_eeprom.hex
ebin: $(PRG)_eeprom.bin
esrec: $(PRG)_eeprom.srec
%_eeprom.hex: %.elf
$(OBJCOPY) -j .eeprom --change-section-lma .eeprom=0 -O ihex $< $@
%_eeprom.srec: %.elf
$(OBJCOPY) -j .eeprom --change-section-lma .eeprom=0 -O srec $< $@
%_eeprom.bin: %.elf
$(OBJCOPY) -j .eeprom --change-section-lma .eeprom=0 -O binary $< $@
clean:
rm -rf *.o $(PRG).elf *.lst *.map *.bin *.hex *.srec *.tmp
program:
avrdude $(AD_CONFIG) -U flash:w:$(PRG).hex
program_fuses:
avrdude $(AD_CONFIG) -u -U lfuse:w:$(AD_LOFUSE):m
avrdude $(AD_CONFIG) -u -U hfuse:w:$(AD_HIFUSE):m
main.avr (tavrasm program)
.include "m16def.inc"
.equ LCD_PIN = PINA
.equ LCD_PORT = PORTA
.equ LCD_PORT0 = PORTA0
.equ LCD_PORT1 = PORTA1
.equ LCD_PORT2 = PORTA2
.equ LCD_PORT3 = PORTA3
.equ LCD_PORT4 = PORTA4
.equ LCD_PORT5 = PORTA5
.equ LCD_PORT6 = PORTA6
.equ LCD_PORT7 = PORTA7
.equ LCD_DDR = DDRA
.equ LCD_RW = LCD_PORT4
.equ LCD_RS = LCD_PORT6
.equ LCD_E = LCD_PORT5
.equ LCD_CLEAR = 0b00000001 ; clear display
.equ LCD_HOME = 0b00000010 ; return home
.equ LCD_CURSOR = 0b00000110 ; set Cursor
.equ LCD_ON = 0b00001110 ; LCD on
.equ LCD_SET = 0b00101100 ; 8 bits, 2 lines, 5x7dots
.equ LCD_4BIT = 0b00000010 ; 4 bit mode
.equ LCD_WIRING = 0b11100000
.def char = R0
.def buffer = R16
.def counter = R17
.def temp = R18
.def wait0 = R21
.def wait1 = R22
.def delay0 = R23
.def delay1 = R24
.CSEG
.ORG 0x00
rjmp init
_delayproc:
ldi wait1, 50
_delayproc_0:
dec wait0
brne _delayproc_0
dec wait1
brne _delayproc_0
ret
LCD_inst:
cbi LCD_PORT, LCD_RS
rjmp LCD_write
LCD_data:
sbi LCD_PORT, LCD_RS
LCD_write:
in temp, LCD_PORT
push buffer
swap buffer
andi buffer, 0x0f
or buffer, temp
out LCD_PORT, buffer
sbi LCD_PORT, LCD_E
rcall _delayproc
cbi LCD_PORT, LCD_E
pop buffer
andi buffer, 0x0f
or buffer, temp
out LCD_PORT, buffer
sbi LCD_PORT, LCD_E
rcall _delayproc
cbi LCD_PORT, LCD_E
clr temp
out LCD_PORT, temp
ret
LCD_init:
rcall _delayproc
ldi buffer, 0x30
rcall LCD_inst
rcall _delayproc
ldi buffer, LCD_4BIT
out LCD_PORT, buffer
sbi LCD_PORT, LCD_E
rcall _delayproc
cbi LCD_PORT, LCD_E
ldi buffer, 0x28
rcall LCD_inst
ldi buffer, LCD_ON
rcall LCD_inst
ldi buffer, LCD_CLEAR
rcall LCD_inst
ldi buffer, LCD_HOME
rcall LCD_inst
ret
init:
ldi temp, $FF
out spl, temp
ser temp
out LCD_DDR, temp ; LCD_PORT output
main:
rcall LCD_init
ldi ZL, LOW(tabel*2)
ldi ZH, HIGH(tabel*2)
tloop:
lpm
mov temp, char
cpi temp, '#'
breq tloop1
mov buffer, char ; Jump if send buffer empty
rcall LCD_data
inc ZL ; next character
brne tloop ; next character
tloop1:
ldi temp, LCD_WIRING
out LCD_DDR, temp
ldi temp, 0b00011111
out LCD_PORT, temp
_main:
ldi delay0, 0x0
ldi delay1, 0x0
_delay:
dec delay0
brne _delay
dec delay1
brne _delay
rjmp _main
tabel:
.DB "Welcome to Hlektronika.gr#"
makefile for main.avr
UMCU = atmega16
PORT = /dev/ttyS0
UISP = uisp
BOARD = stk500
DEFS = /opt/avr/share/defs
SRC = main.avr
HEX = main.hex
all: hex
hex:
tavrasm -I $(DEFS) $(SRC)
clean:
rm -rf $(HEX)
program :
$(UISP) -dprog=$(BOARD) -dserial=$(PORT) -dpart=$(UMCU) --erase
$(UISP) -dprog=$(BOARD) -dserial=$(PORT) -dpart=$(UMCU) --upload if=$(HEX) -v=2
# $(UISP) -dprog=$(BOARD) -dserial=$(PORT) -dpart=$(UMCU) --wr_fuse_l=0xee
erase :
$(UISP) -dprog=$(BOARD) -dserial=$(PORT) -dpart=$(UMCU) --erase
Το manual για τις HD44780 το έβαλα στην σελίδα μου επειδή είναι χρήσιμο και επειδή το πισί μ
δεν είναι ανοιχτό πάντα βάλτε το αρχείο στα downloads
http://pet.homeunix.org/HD44780.pdf