Im having an issue iwth the Pico_I2C_Lcd file

II dont know how to fix this, can anyone help?

hi im not sure what ive done wrong I followed each of your steps exactly but something is not quite right the screen comes on so it is definitely getting power however the cursor is not showing up and neither is any characters the screen is just flashing (turning on and off)

I had this running several times and today I went to work on my code and before I ran it I tested my working code and I now get this error below. I also get the same error running your test code. What could it be?

Running test_main Traceback (most recent call last): File "<stdin>", line 62, in <module> File "<stdin>", line 16, in test_main File "pico_i2c_lcd.py", line 22, in __init__ OSError: [Errno 5] EIO

can you include a license to this project?
https://choosealicense.com

Hello! I used your library with my Pico to my alarm project. I used the LCD to type in the PIN needed to arm and disarm the alarm. My code utilises a while loop to await input from the keypad and then print a typed number on the LCD. I noticed that with every character printed a lot of memory of my Pico is being consumed. Apart from printstr() function I also noticed that lcd.clear() consumes a lot of memory too. When it's executed in a loop it takes all the memory from my Pico and the microcontroller freezes. I got rid of lcd.clear() function in my loop, but eveytime I printed a character on the LCD it still took memory. What I did was adding GarbageCollector library and adding a line with gc.collect() at the end of every function in pico_i2c_lcd.py. This really helped! Now any function from your library barely takes any memory off my microcontroller. I think you should add those lines to your code.

`import utime

from lcd_api import LcdApi
from machine import I2C
import gc

MASK_RS = 0x01
MASK_RW = 0x02
MASK_E = 0x04

SHIFT_BACKLIGHT = 3
SHIFT_DATA = 4

class I2cLcd(LcdApi):

def __init__(self, i2c, i2c_addr, num_lines, num_columns):
    self.i2c = i2c
    self.i2c_addr = i2c_addr
    self.i2c.writeto(self.i2c_addr, bytes([0]))
    utime.sleep_ms(20)   # Allow LCD time to powerup
    self.hal_write_init_nibble(self.LCD_FUNCTION_RESET)
    utime.sleep_ms(5)    # Need to delay at least 4.1 msec
    self.hal_write_init_nibble(self.LCD_FUNCTION_RESET)
    utime.sleep_ms(1)
    self.hal_write_init_nibble(self.LCD_FUNCTION_RESET)
    utime.sleep_ms(1)
    self.hal_write_init_nibble(self.LCD_FUNCTION)
    utime.sleep_ms(1)
    LcdApi.__init__(self, num_lines, num_columns)
    cmd = self.LCD_FUNCTION
    if num_lines > 1:
        cmd |= self.LCD_FUNCTION_2LINES
    self.hal_write_command(cmd)
    gc.collect()

def hal_write_init_nibble(self, nibble):
    byte = ((nibble >> 4) & 0x0f) << SHIFT_DATA
    self.i2c.writeto(self.i2c_addr, bytes([byte | MASK_E]))
    self.i2c.writeto(self.i2c_addr, bytes([byte]))
    gc.collect()
    
def hal_backlight_on(self):
    self.i2c.writeto(self.i2c_addr, bytes([1 << SHIFT_BACKLIGHT]))
    gc.collect()
    
def hal_backlight_off(self):
    self.i2c.writeto(self.i2c_addr, bytes([0]))
    gc.collect()
    
def hal_write_command(self, cmd):
    byte = ((self.backlight << SHIFT_BACKLIGHT) |
            (((cmd >> 4) & 0x0f) << SHIFT_DATA))
    self.i2c.writeto(self.i2c_addr, bytes([byte | MASK_E]))
    self.i2c.writeto(self.i2c_addr, bytes([byte]))
    byte = ((self.backlight << SHIFT_BACKLIGHT) |
            ((cmd & 0x0f) << SHIFT_DATA))
    self.i2c.writeto(self.i2c_addr, bytes([byte | MASK_E]))
    self.i2c.writeto(self.i2c_addr, bytes([byte]))
    if cmd <= 3:
        utime.sleep_ms(5)
    gc.collect()

def hal_write_data(self, data):
    byte = (MASK_RS |
            (self.backlight << SHIFT_BACKLIGHT) |
            (((data >> 4) & 0x0f) << SHIFT_DATA))
    self.i2c.writeto(self.i2c_addr, bytes([byte | MASK_E]))
    self.i2c.writeto(self.i2c_addr, bytes([byte]))
    byte = (MASK_RS |
            (self.backlight << SHIFT_BACKLIGHT) |
            ((data & 0x0f) << SHIFT_DATA))      
    self.i2c.writeto(self.i2c_addr, bytes([byte | MASK_E]))
    self.i2c.writeto(self.i2c_addr, bytes([byte]))
    gc.collect()

`

Hello and thanks for the LCD code. I have a Pi Pico W, Windows 10, Thonny 4.1.4 on COM7, 2x16 LCD. I have written and run several small test programs successfully including an i2c scan which shows LCD on 0x27 when run both from "computer" and "pi". I have modified pico_i2c_test.py to support my hookup and slowing the clock freq:
I2C_NUM_ROWS = 2
I2C_NUM_COLS = 16
i2c = I2C(0, sda=machine.Pin(20), scl=machine.Pin(21), freq=100000)
Copied 3 files to Pi without renaming. However, when I run pico_i2c_test.py I get the following error:

MPY: soft reboot
Running test_main
Traceback (most recent call last):
File "", line 62, in
File "", line 16, in test_main
File "pico_i2c_lcd.py", line 22, in init
OSError: [Errno 5] EIO

This is referencing this line 22 in pico_i2c_lcd.py:
self.i2c.writeto(self.i2c_addr, bytes([0])) # (this statement fails - put "print" statements before & after)

Note that a scan does detect i2c on 0x27. Rewired with shorter leads and slowed i2c clock -> no joy. I am not an accomplished Python programmer and consequently cannot troubleshoot the problem any further. Thanks again for any help.

So! This is just for your chuckles and anyone else who might have the same problem. After spending hours on the problem, while hooking up my scope to SCL and SDA the system rebooted and works!

Hello,
Just trying your code for driving 16x2 LCD on Raspberry Pi Pico using Micropython.
Have followed your instructions and copied the files onto the Pico.
Edited the parameters and when I try to run I get and error when the code tries to
import smbus

If I run this from the command prompt the inbuilt library is not found.
Please advise.
Regards
Phil Green

Hi I have a LCD 1602 and am unable to get the address,
running the code below : -

import machine sda=machine.Pin(0) scl=machine.Pin(1) i2c=machine.I2C(0,sda=sda,scl=scl, freq=400000) print(i2c.scan())

the output is
`>>> %Run -c $EDITOR_CONTENT
[]

`

Hello,

I have copied the 3 files on to the pico. However Thonny returns ImportError: no module named "lcd_api" and no module named "pico_i2c_lcd"

What am I doing wrong ?

Best regards
Kim

Hello there,

I'm on a small project on Raspberry Pi Pico with a 2 line 1602 I2C LCD using your library.

I found out that my code was desperately slow.

Debugging, I found out that my code spent 95% of its time in the display routine, debugging more showed it spent 90% of the time in pico_I2c_lcd.

So I took a look at it and found out it was because your library calls gc.collect() FOR EACH AND EVERY ACTION.

So each time you put a char on screen you perform a memory garbage collection afterwards ?!

I found out that this comes from the issue #5 and this spurious code was added by user [n0n3nt1ty]

Garbage collection may be performed manually once at each iteration of the main program loop, but should never be buried down in a library that will be called hundreds of times !

So I removed the importation of gc from my copy of the library, removed all the gc.collect() stupid calls, and while I was at it, replace all the "utime" by "time".

Net result : My code using this fixed version of the library runs 10 times faster...

I get this error while running the test (I know that my hexadecimal is correct.)
Traceback (most recent call last): File "<stdin>", line 62, in <module> File "<stdin>", line 16, in test_main File "pico_i2c_lcd.py", line 22, in __init__ OSError: [Errno 5] EIO

How can I fix this?

Is there a way you can clear rows of a 4X20 LCD and not the entire LCD? Thanks!

Hello,

I have some minor issues with using the scan.py as well as getting anything loaded onto the LCD screen.
I was going to post a screenshot, but github isn't allowing that at this time for some reason.
Upon running the scan.py script, I receive an array for the LCD address as follows in HEX:
[62, 96, 112]
and converted to decimal with make it
[3E, 60, 70]
This is strange as there should only be one address.
Either way, through troubleshooting, all 3 values work, if used separately, in the test.py script, as it runs and goes each line of testing script for the LCD, but the LCD doesn't illuminate or anything.
If the whole array is used, an error message occurs. Please help on this matter. 3 addresses is strange, and no LCD illumination or messaging is not helping. Thank you.

-Dom