47 lines
1.8 KiB
Text
47 lines
1.8 KiB
Text
|
- HD44780 LCD SUPPORT -
|
||
|
|
|
||
|
|
Support for the HD44780 LCD is via the wiringPi library available at
|
||
|
|
http://wiringpi.com/download-and-install/ which must be installed in all cases.
|
||
|
|
|
||
|
|
The HD44780 in 4-bit mode is probably the most common connection method and
|
||
|
|
wiring details can be found at http://wiringpi.com/dev-lib/lcd-library/
|
||
|
|
|
||
|
|
To compile MMDVMHost with support for the HD44780 use the following commands.
|
||
|
|
|
||
|
|
# cp Makefile.Pi.HD44780 Makefile
|
||
|
|
# make clean
|
||
|
|
# make
|
||
|
|
|
||
|
|
Other HD44780 variations exist that connect via I2C. Support is also via
|
||
|
|
wiringPi, but to compile for each I2C device requires a different Makefile
|
||
|
|
depending on the IC attached to the LCD.
|
||
|
|
|
||
|
|
- ADAFRUIT RGB LCD SHIELD -
|
||
|
|
|
||
|
|
The Adafruit RGB LCD Shield is available from https://www.adafruit.com/product/714
|
||
|
|
I2C is via the MCP23017 IC and is enabled with Makefile.Pi.Adafruit. The
|
||
|
|
I2C device address in MMDVM.ini should be set to 0x20.
|
||
|
|
|
||
|
|
- PCF8574 IC -
|
||
|
|
|
||
|
|
HD44780 LCDs connected via a PCF8574 Remote 8-Bit I/O Expander are available on
|
||
|
|
eBay for very little money! This IC uses Makefile.Pi.PCF8574 and the I2C
|
||
|
|
device address should be set to 0x27.
|
||
|
|
|
||
|
|
- BEWARE -
|
||
|
|
|
||
|
|
The I2C device address can be manually configured on some devices!
|
||
|
|
|
||
|
|
- CHECK YOUR ACTUAL DEVICE ADDRESS -
|
||
|
|
|
||
|
|
More information on configuring and using I2C on the RPi including how to probe
|
||
|
|
the I2C bus for device addresses can be found at
|
||
|
|
https://learn.sparkfun.com/tutorials/raspberry-pi-spi-and-i2c-tutorial#i2c-on-pi
|
||
|
|
|
||
|
|
- PWM BACKLIGHT CONTROL -
|
||
|
|
|
||
|
|
Whilst connected in 4-bit mode or via the PCF8574 IC, the LED backlight can be
|
||
|
|
wired for control via PWM. Connect the backlight +ve pin to any spare GPIO pin
|
||
|
|
and configure MMDVM.ini as appropriate. By default, wiringPi pin 21 is
|
||
|
|
configured.
|