# RPI-PICO-I2C-LCD
This is a project which adapts code from another user to allow usage of the PCF8574 I2C lcd backpack for either 20x4 or 16x2 lcd screens.
+
+Credit: https://github.com/dhylands/python_lcd/tree/master/lcd mostly to Dave Hylands for the basic api and lcd driver code.
+
+This is code adaptded for micropython and the Raspberry Pi PICO specifically.
+
+Usage:
+- Download all 3 .py files included.
+- Open Thonny IDE with the 3 files
+- Make pin edits or setup changes (See below for options)
+- DO NOT EDIT FILE NAMES!
+- In Thonny, go to top menu File => Save Copy => Raspberry Pi Pico and save each .py file to the board.
+- Switch to the main.py and click run. This should be able to initalize the LCD display if settings are right.
+- If you get errors, see below for a known list of errors and their fixes
+- Wiring Diagram LCD_bb.jpg! Please look here for a fritzing diagram!
+
+Requirements:
+- 3.3 - 5V level translator. This is crucial to encure the lcd recieves the commands properly. I recommend this: https://www.adafruit.com/product/757 (Must be Bi-Directional)
+- PCF8574 I2C LCD backpack. (These are common to find)
+
+Setup Changes:
+- Make sure the top address is set correctly!
+Use this small program to scan for I2C devices:
+
+import machine
+sda=machine.Pin(0)
+scl=machine.Pin(1)
+i2c=machine.I2C(0,sda=sda, scl=scl, freq=400000)
+print(i2c.scan())
+
+- Once you get an address through the console (REPL), this will be in decimal and not hex. You can convert the decimal to hex or simply put a decimal address in the setup.
+in my case, the decimal addr. was 39 which converts to 0x27 in hex.
+- Ensure that your SCL and SDA pins are selected properly in accordance with the Pico's pin table. These connect to the low voltage side of the translator with a 3.3V Reference from the board. The high voltage side gets a 5V reference from the VBUS pin of the Pico.
+- Finally, assure the I2C_NUM_ROWS and I2C_NUM_COLS are set properly!
+
+Usage:
+
+Printing is simple :lcd.putstr("") This requires a string input! if you want to feed a changing value such as a temperature, it must be: lcd.putstr(str(Variable))
+
+Errors:
+
+OSERROR : 5 (This is quite a common error, 5 means I/O error. Check Your connections. This means codes can't be sent or recieved ensure SCL and SDA are properly connected through the level translator!
+
+Feel to leave comments or questions and I will try to answer them as quick as possible!
projects / RPI-PICO-I2C-LCD.git / blobdiff