MicroPython Forum (Archive)

RajaRamesh wrote: ↑

Wed Jun 12, 2019 4:28 am

dhylands wrote: ↑

Tue Jun 11, 2019 5:23 pm

I recorded a video here: https://www.youtube.com/watch?v=KiR-r8mXBCo

Thank you dhylands...i will try and get back to you if have any questions.

Hi dhylands, i am trying below code to display text with GpioLcd. but text was not displaying on lcd screen so i stopped going further. do i need to change the pins in below code or do i need to change slc and sda pins. currently i am running below code after connecting slc =Pin(5) sda=Pin(4) from i2c to esp8266.

i used lcd.clear() to clear the screen but it is not happening.

from machine import Pin
from nodemcu_gpio_lcd import GpioLcd
lcd = GpioLcd(rs_pin=Pin(16),enable_pin=Pin(5),d4_pin=Pin(4),d5_pin=Pin(0),d6_pin=Pin(2),d7_pin=Pin(14),num_lines=2, num_columns=16)
lcd.putstr("Hello")

You need to use the i2c version and just extract the code that does the scrolling. The GPIO version doesn't work with LCDs that have i2c backpacks.

In particular, this code:

Hi Dave- 1st of all, thanks for your great work here- got it working on my 8266 & 1602 (with level shifter) without any problems at all.

Can you explain the syntax of putstr(), please? I'm tripping up on the syntax you use in your Test script: lcd.putstr("%7d" % (ticks_ms() // 1000)). Please explain the use of "%". If I substitute the "(ticks_ms() // 1000))" with a variable that holds a number, it prints, but I don't understand what the ""%7d" %" means. (And I couldn't sufficiently decipher lcd_api.py to work it out myself, sorry).

Thanks

This one explains the string formatting: https://pyformat.info/ can also be written as: %7d means convert the int to a left space padded string 7 characters wide.
ie.

Just a couple minor corrections:

That would be '{:7d}'.format(args) - Use a colon and not a percent with the 7d. And '%7d' % 123 produces space padding on the left.

Ooops, thanks Dave!

dhylands wrote: ↑

Sat Jun 15, 2019 4:07 pm

In particular, this code:

Code: Select all

    msg = 'This is a scrolling test. '
    if (len(msg) < lcd.num_columns):
        msg += ' ' * (lcd.num_columns - len(msg))
    for i in range(len(msg)):
        len2 = min(lcd.num_columns, len(msg) - i)
        len1 = lcd.num_columns - len2
        msg2 = ''
        if len2 > 0:
            msg2 += msg[i:i+len2]
        if len1 > 0:
            msg2 += msg[0:len1]
        lcd.move_to(0, 0)
        lcd.putstr(msg2)
        delay(250)

Hi Dave, i have updated i2c version with above code with small correction in for loop. i am getting error when for loop is outside of if statement.so i have mentioned the for loop inside if statement and the text is scrolling on LCD screen in 1st row. i have updated lcd.putstr as lcd.putstr(msg2\nmsg2) to scroll the text on 1st and 2nd row. but it was not working. do we need to have an if statement on lcd.row_num to scroll on 2nd row?

I just got my I2C 20x4 LCD working with esp32. I've used level shifter to adjust 3.3v and 5 v between devices.
A question: is it doable to redirect Micropython REPL to 20x4 LCD?

Apparently yes, see viewtopic.php?t=7083&p=40307