3
|
twi0_sda
|
blue
|
4
|
+5V
|
red
|
|
5
|
twi0_sck
|
green
|
6
|
gnd
|
black
|
or I2C-1,
27
|
twi1_sda
|
blue
|
28
|
twi1_sck
|
green
|
Run i2c detection on bus 0: i2cdetect 0; and the device is detected on 0x62, the default address.
Start by trying a Python version that uses smbus (or smbus2). But all registers read 0.
Try Garmin's LIDARLite_RaspberryPi_Library. Note that the library hard coded the i2c bus to i2c-1. The code compiles and runs fine without modification. Add code to do a register dump,
Add 0.5 sec delay. It prints distance at about 1 Hz. The max update rate appears to be 300Hz , possibly limited by 100KHz I2C speed. Occasionally, there are errors and the kernel prints error message,
sunxi_i2c_do_xfer()985 - [i2c1] incomplete xfer (status: 0x48, dev addr: 0x62)This is using armbian 5.38 with linux image sun8i 3.4.113.
Try to display the distance on the 1.8" LCD. The simplest way is just to redirect the fb console. Use con2fbmap to map a tty console to the fb. And to set to a large font,
sudo setfont -C /dev/tty1 /usr/share/consolefonts/Lat15-TerminusBold14.psf.gzFor something fancier, need a graphics library. The SDL library can be used. Python Pygame can be set to use SDL to test it out. Pygame works fine on the LCD. It is very desirable to stay with Python. So SWIG is used to add python interface to the Garmin library. With that, the LCD displays the distance nicely. However, there are some unresolved issues with console/framebuffer management. The other option is just to write to the framebuffer directly as images. Note that the format is hardware dependent; for this particular LCD, the format is packed 16-bit RGB (5/6/5).
