micropython玩ESP8266(nodemcu)I2C连接1602液晶

zxy882266 · 发表于 2020-5-3 23:25:04

一直在研究8266 iic 1602 在ESP8266(nodemcu)I2C连接1602液晶
https://www.mydigit.cn/forum.php?mod=viewthread&tid=150235
已经把ARDUIN下调通了，主要是电源问题，3.3伏下背光调不上来，看不清楚
这次是在伟大的micropython下搞的，其实是和那个一起研究的，1602点不亮就啥也玩不了，在ARDUINO 下搞定后，
今天成功在micropython下点亮IIC 1602，这样留再也不用为8266缺少引脚发愁了，快搞了一个月了，
这方面资料少，所以贡献给大家，少走弯路，翻Q真麻烦，用翻译软件硬一点点肯，micropython知道成功点亮，但程序还没搞懂
剩下的就简单了，顺便吧micropython库发来，也可以翻Q去下
micropython和ARDUINO好像不通用，没仔细研究，有懂的交流下

lyy-cy · 发表于 2020-5-5 11:37:17

"""Implements a HD44780 character LCD connected via PCF8574 on I2C.
This was tested with: https://www.wemos.cc/product/d1-mini.html"""

from drivers import lcd_api
from machine import I2C
from time import sleep_ms

# The PCF8574 has a jumper selectable address: 0x20 - 0x27
DEFAULT_I2C_ADDR = 0x27

# Defines shifts or masks for the various LCD line attached to the PCF8574

MASK_RS = 0x01
MASK_RW = 0x02
MASK_E = 0x04
SHIFT_BACKLIGHT = 3
SHIFT_DATA = 4

class I2c_Lcd(lcd_api.Lcd_Api):
"""Implements a HD44780 character LCD connected via PCF8574 on I2C."""

def __init__(self, i2c, i2c_addr, num_lines, num_columns):
      self.i2c = i2c
      self.i2c_addr = i2c_addr
      self.i2c.writeto(self.i2c_addr, bytearray([0]))
      sleep_ms(20) # Allow LCD time to powerup
      # Send reset 3 times
      self.hal_write_init_nibble(self.LCD_FUNCTION_RESET)
      sleep_ms(5) # need to delay at least 4.1 msec
      self.hal_write_init_nibble(self.LCD_FUNCTION_RESET)
      sleep_ms(1)
      self.hal_write_init_nibble(self.LCD_FUNCTION_RESET)
      sleep_ms(1)
      # Put LCD into 4 bit mode
      self.hal_write_init_nibble(self.LCD_FUNCTION)
      sleep_ms(1)
      lcd_api.Lcd_Api.__init__(self, num_lines, num_columns)
      cmd = self.LCD_FUNCTION
      if num_lines > 1:
         cmd |= self.LCD_FUNCTION_2LINES
      self.hal_write_command(cmd)

def hal_write_init_nibble(self, nibble):
      """Writes an initialization nibble to the LCD.
      This particular function is only used during initialization.
      """
      byte = ((nibble >> 4) & 0x0f) << SHIFT_DATA
      self.i2c.writeto(self.i2c_addr, bytearray([byte | MASK_E]))
      self.i2c.writeto(self.i2c_addr, bytearray([byte]))

def hal_backlight_on(self):
      """Allows the hal layer to turn the backlight on."""
      self.i2c.writeto(self.i2c_addr, bytearray([1 << SHIFT_BACKLIGHT]))

def hal_backlight_off(self):
      """Allows the hal layer to turn the backlight off."""
      self.i2c.writeto(self.i2c_addr, bytearray([0]))

def hal_write_command(self, cmd):
      """Writes a command to the LCD.
      Data is latched on the falling edge of E.
      """
      byte = ((self.backlight << SHIFT_BACKLIGHT) | (((cmd >> 4) & 0x0f) << SHIFT_DATA))
      self.i2c.writeto(self.i2c_addr, bytearray([byte | MASK_E]))
      self.i2c.writeto(self.i2c_addr, bytearray([byte]))
      byte = ((self.backlight << SHIFT_BACKLIGHT) | ((cmd & 0x0f) << SHIFT_DATA))
      self.i2c.writeto(self.i2c_addr, bytearray([byte | MASK_E]))
      self.i2c.writeto(self.i2c_addr, bytearray([byte]))
      if cmd <= 3:
         # The home and clear commands require a worst case delay of 4.1 msec
         sleep_ms(5)

def hal_write_data(self, data):
      """Write data to the LCD."""
      byte = (MASK_RS | (self.backlight << SHIFT_BACKLIGHT) | (((data >> 4) & 0x0f) << SHIFT_DATA))
      self.i2c.writeto(self.i2c_addr, bytearray([byte | MASK_E]))
      self.i2c.writeto(self.i2c_addr, bytearray([byte]))
      byte = (MASK_RS | (self.backlight << SHIFT_BACKLIGHT) | ((data & 0x0f) << SHIFT_DATA))
      self.i2c.writeto(self.i2c_addr, bytearray([byte | MASK_E]))
      self.i2c.writeto(self.i2c_addr, bytearray([byte]))