Eating up the memory

[n0n3nt1ty]

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()

`

[T-622]

Please submit this as a pull request so I can merge and keep track of code changes

[T-622]

Very good work by the way!

[n0n3nt1ty]

Very good work by the way!

You're welcome! I'm sorry but I'm new to GitHub and don't know how to create that Pull request. Could you help?