Need help with an I2C LCD display
June 16, 2024, 13:28
I have a breadboard with Raspberry Pi Pico on it and connected an I2C LCD Display. I can't get the LCD to "work" though. Can't print anything on it despite having the libraries installed on the micro controller. I've tried .putstr and .putchar but neither work, although .backlight_on and .backlight_off work. If this makes things clearer, I have a 2x16 LCD with I2C LCM1602 converter
is it something like this?
matter of fact, wait, this is it
could you show the code
and double check if all the pins are correct
oh yeah also
this is correct
this is not
It's literally the same model, bought from Botland as well
yeah that makes sense
but show the code
py
import utime
import machine
from machine import I2C, Pin
from lcd_api import LcdApi
from pico_i2c_lcd import I2cLcd
I2C_ADDR = 0x27
I2C_NUM_ROWS = 2
I2C_NUM_COLS = 16
sda = Pin(0)
scl = Pin(1)
i2c = I2C(0, sda=sda, scl=scl, freq=400000)
lcd = I2cLcd(i2c, I2C_ADDR, I2C_NUM_ROWS, I2C_NUM_COLS)
lcd.clear()
lcd.move_to(5,0)
lcd.putstr("Howdy")
utime.sleep(2)
Yeah SDA going to Pin(0) and SCL to Pin(1)
This is just one of many test codes I've tried to run anything on my LCD
\\\py
[code]
\\\
do this instead
The original code I've tried as well was from the tomshardware site:
py
from machine import I2C, Pin
from time import sleep
from pico_i2c_lcd import I2cLcd
i2c = I2C(0, sda=Pin(0), scl=Pin(1), freq=400000)
I2C_ADDR = i2c.scan()[0]
lcd = I2cLcd(i2c, I2C_ADDR, 2, 16)
while True:
print(I2C_ADDR)
lcd.blink_cursor_on()
lcd.putstr("I2C Address:"+str(I2C_ADDR)+"\n")
lcd.putstr("Tom's Hardware")
sleep(2)
lcd.clear()
lcd.putstr("I2C Address:"+str(hex(I2C_ADDR))+"\n")
lcd.putstr("Tom's Hardware")
sleep(2)
lcd.blink_cursor_off()
lcd.clear()
lcd.putstr("Backlight Test")
for i in range(10):
lcd.backlight_on()
sleep(0.2)
lcd.backlight_off()
sleep(0.2)
lcd.backlight_on()
lcd.hide_cursor()
for i in range(20):
lcd.putstr(str(i))
sleep(0.4)
lcd.clear()
py
from machine import I2C # type: ignore
from machine import Pin as pin # type: ignore
from lcd_api import LcdApi
from pico_i2c_lcd import I2cLcd
I2C_ADDR = 0x27
I2C_NUM_ROWS = 2
I2C_NUM_COLS = 16
i2c = I2C(0, sda=pin(0), scl=pin(1), freq=400000)
lcd = I2cLcd(i2c, I2C_ADDR, I2C_NUM_ROWS, I2C_NUM_COLS)
lcd.putstr("hello world")
see if this works
this works for me
i have the exact same model
Nope, doesn't work either
probably means the pins are wrong then
I'll be numering by physical pins, so
GND 28, power 40, SDA 1 and SCL 2
gnd - gnd
vcc - vbus or vsys
sda - gp0, pin 1
scl - gp1, pin 2
Yup, that's how I got it done
is the backlight on at least?
also, from the front the text is pretty much invisible
so look at it from an angle
Yeah, other commands such as .backlight_off/on work
I checked all the angles already as well
are you absolutely sure the breadboard connections arent wrong
Wait. I see really FAINT image of the text, is it supposed to be THAT barely visible?
yes.
💀
apparently so
Oh damn... Should I get myself a different LCD perhaps? A more visible one?
i mean its your lcd
i dont really need anything more
so i didnt get another
Any way to set the contrast higher then?
i dont believe there is one no
Anyway, thanks a lot for the help :)
I figured it out, on the I2C board there's a potentiometer taht u can rotate with a screwdriver
WAIT HOLY FUCK THERE IS??
Voltage control = contrast control
It's now bright as day for me lol
YOOOOO
HOL ON
I DID NOT KNOW THIS
oooohhh thats what that was
Hahaha it took me a while, I just found a youtube video explaining it
holy crap man thanks for figuring this out
i thought i was stuck with it being invisible