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Enable I2C support on OpenWRT/LEDE @ Raspberry Pi (1 model B)
Raw
enable_i2c_openwrt_rpi1.md

Enable I2C on OpenWRT/LEDE @ Raspberry Pi (1 model B)

/boot/config.txt

Edit this file on any computer, insert the SD card and create/enter the boot folder located at the FAT32 partition (it's very small, ~20MB).

Contents of the config.txt file:

dtparam=i2c_arm=on
dtparam=i2c0=on
dtparam=i2c1=on
dtparam=spi=on
dtparam=i2s=on

Packages installed through OPKG

KMOD

  • i2c-tools - 3.1.2-1
  • kmod-i2c-gpio - 4.4.92-1
  • kmod-i2c-gpio-custom - 4.4.92-2
  • kmod-i2c-algo-bit - 4.4.14-1
  • kmod-i2c-algo-pcf - 4.4.14-1
  • kmod-i2c-bcm2708 - 4.4.14-1
  • kmod-i2c-bcm2835 - 4.4.14-1
  • kmod-i2c-core - 4.4.14-1
  • kmod-i2c-gpio - 4.4.14-1
  • kmod-i2c-gpio-custom - 4.4.14-2
  • kmod-i2c-mux - 4.4.14-1
opkg install i2c-tools kmod-i2c-gpio kmod-i2c-gpio-custom kmod-i2c-algo-bit kmod-i2c-algo-pcf kmod-i2c-bcm2708 kmod-i2c-bcm2835 kmod-i2c-core kmod-i2c-gpio kmod-i2c-gpio-custom kmod-i2c-mux

Python SMBUS

  • python-smbus - 3.1.2-1
  • python3-smbus - 3.1.2-1
opkg install python-smbus python3-smbus

Test i2c

i2cdetect -y 0
i2cdetect -y 1

root@LEDE-RPi:~/scripts# i2cdetect -y 0
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- -- 
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
70: -- -- -- -- -- -- -- --                         
root@LEDE-RPi:~/scripts# i2cdetect -y 1
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- -- 
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 3f 
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
70: -- -- -- -- -- -- -- --

Source

Raw
lcd_i2c.py
#!/usr/bin/python
#--------------------------------------
# ___ ___ _ ____
# / _ \/ _ \(_) __/__ __ __
# / , _/ ___/ /\ \/ _ \/ // /
# /_/|_/_/ /_/___/ .__/\_, /
# /_/ /___/
#
# lcd_i2c.py
# LCD test script using I2C backpack.
# Supports 16x2 and 20x4 screens.
#
# Author : Matt Hawkins
# Date : 20/09/2015
# Edited by EnforcerZhukov (https://www.github.com/enforcerzhukov)
# on Feb 2018
#
# http://www.raspberrypi-spy.co.uk/
#
# Copyright 2015 Matt Hawkins
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
#
#--------------------------------------
import smbus
import time
import atexit
# Define some device parameters
I2C_ADDR = 0x3F # I2C device address
LCD_WIDTH = 16 # Maximum characters per line
# Define some device constants
LCD_CHR = 1 # Mode - Sending data
LCD_CMD = 0 # Mode - Sending command
LCD_LINE_1 = 0x80 # LCD RAM address for the 1st line
LCD_LINE_2 = 0xC0 # LCD RAM address for the 2nd line
LCD_LINE_3 = 0x94 # LCD RAM address for the 3rd line
LCD_LINE_4 = 0xD4 # LCD RAM address for the 4th line
LCD_BACKLIGHT = 0x08 # On
#LCD_BACKLIGHT = 0x00 # Off
ENABLE = 0b00000100 # Enable bit
# Timing constants
E_PULSE = 0.0005
E_DELAY = 0.0005
#Open I2C interface
#bus = smbus.SMBus(0) # Rev 1 Pi uses 0
bus = smbus.SMBus(1) # Rev 2 Pi uses 1
def lcd_init():
# Initialise display
lcd_byte(0x33,LCD_CMD) # 110011 Initialise
lcd_byte(0x32,LCD_CMD) # 110010 Initialise
lcd_byte(0x06,LCD_CMD) # 000110 Cursor move direction
lcd_byte(0x0C,LCD_CMD) # 001100 Display On,Cursor Off, Blink Off
lcd_byte(0x28,LCD_CMD) # 101000 Data length, number of lines, font size
lcd_byte(0x01,LCD_CMD) # 000001 Clear display
time.sleep(E_DELAY)
def lcd_byte(bits, mode):
# Send byte to data pins
# bits = the data
# mode = 1 for data
# 0 for command
bits_high = mode | (bits & 0xF0) | LCD_BACKLIGHT
bits_low = mode | ((bits<<4) & 0xF0) | LCD_BACKLIGHT
# High bits
bus.write_byte(I2C_ADDR, bits_high)
lcd_toggle_enable(bits_high)
# Low bits
bus.write_byte(I2C_ADDR, bits_low)
lcd_toggle_enable(bits_low)
def lcd_toggle_enable(bits):
# Toggle enable
time.sleep(E_DELAY)
bus.write_byte(I2C_ADDR, (bits | ENABLE))
time.sleep(E_PULSE)
bus.write_byte(I2C_ADDR,(bits & ~ENABLE))
time.sleep(E_DELAY)
def lcd_string(message,line):
# Send string to display
message = message.ljust(LCD_WIDTH," ")
lcd_byte(line, LCD_CMD)
for i in range(LCD_WIDTH):
lcd_byte(ord(message[i]),LCD_CHR)
def lcd_clear():
# Clear LCD screen
lcd_byte(0x01, LCD_CMD)
def main():
# Main program block
# Initialise display
lcd_init()
while True:
# Send some test
lcd_string("RPiSpy",LCD_LINE_1)
lcd_string("I2C LCD",LCD_LINE_2)
time.sleep(3)
# Send some more text
lcd_string("RPiSpy",LCD_LINE_1)
lcd_string("I2C LCD",LCD_LINE_2)
time.sleep(3)
if __name__ == '__main__':
try:
main()
except KeyboardInterrupt:
pass
finally:
#lcd_byte(0x01, LCD_CMD)
lcd_clear()
else:
lcd_init()
@atexit.register
def atexit_f():
lcd_clear()
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