u8g2-copy/sys/arm-linux

U8g2 for arm-linux has been modified to use c-periphery userspace library.

• Deprecated sysfs method is no longer used for GPIO thus increasing speed and stability.
• GPIO pins can be unallocated which is useful for testing multiple times.
• I2C and SPI also use c-periphery.

Download U8g2 project

• cd ~/
• git clone --depth 1 https://github.com/olikraus/u8g2

Modify source as needed

Currently GPIO device, I2C and SPI buses are hard coded in u8g2port.c.

• Change values as needed
• nano ~/u8g2/sys/arm-linux/port/u8g2port.c
• Change example (SPI 4 wire hardware for instance)
• nano ~/u8g2/sys/arm-linux/examples/c-examples/u8g2_4wire_hw_spi\u8g2_4wire_hw_spi.c
• Change the DC and RESET as needed (NanoPi Duo here using tx1 and rx1)
• #define OLED_SPI_PIN_RES 199
• #define OLED_SPI_PIN_DC 198

Build source with GPIO character device

• cd ~/u8g2/sys/arm-linux
• make CPPFLAGS=-DPERIPHERY_GPIO_CDEV_SUPPORT=1 CC=gcc CXX=g++

Build source with GPIO sysfs

• cd ~/u8g2/sys/arm-linux
• make CC=gcc CXX=g++