Raspberry Pi: small TFT LCD

since: 2016/08/31
update: 2016/09/13
reference:
1. Home · notro/fbtft Wiki

測試硬體: 1.8" TFT LCD ST7735R (160x128)

A. Pi 啟用 SPI 功能
     $ sudo raspi-config
        > Advanced Options
        > A5 SPI    Enable/Disable automatic loading of SPI kernel module (needed for e.g. PiFace)
        > Enable

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B. 查詢支援的 fbtft_device
    $ sudo modprobe fbtft_device name=list; dmesg | tail -50
      ...
      [ 1262.538743] fbtft_device: Supported displays:
      [ 1262.538751] fbtft_device: adafruit18
      [ 1262.538758] fbtft_device: adafruit18_green
      ....

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C. 載入 Framebuffer TFT LCD 設備
    $ sudo modprobe fbtft_device name=adafruit18

    p.s. There is one required module parameter, and that is name. It specifies which display (device) to register.

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D. 查詢是否載入成功
    $ ls -al /dev/fb*
    /dev/fb0 ----> default display output
    /dev/fb1 ----> fbtft

    $ dmesg
[ 2532.384028] fbtft_device: module is from the staging directory, the quality is unknown, you have been warned.
[ 2532.391421] spidev spi0.0: spidev spi0.0 500kHz 8 bits mode=0x00
[ 2532.391453] spidev spi0.1: spidev spi0.1 500kHz 8 bits mode=0x00
[ 2532.391494] bcm2708_fb soc:fb: soc:fb id=-1 pdata? no
[ 2532.391549] spidev spi0.0: Deleting spi0.0
[ 2532.392348] fbtft_device: GPIOS used by 'adafruit18':
[ 2532.392368] fbtft_device: 'reset' = GPIO25
[ 2532.392377] fbtft_device: 'dc' = GPIO24
[ 2532.392385] fbtft_device: 'led' = GPIO18
[ 2532.392402] spidev spi0.1: spidev spi0.1 500kHz 8 bits mode=0x00
[ 2532.392418] spi spi0.0: fb_st7735r spi0.0 32000kHz 8 bits mode=0x00
[ 2532.425447] fb_st7735r: module is from the staging directory, the quality is unknown, you have been warned.
[ 2533.359781] graphics fb1: fb_st7735r frame buffer, 128x160, 40 KiB video memory, 4 KiB DMA buffer memory, fps=20, spi0.0 at 32 MHz

    $ dmesg | grep graphics
[ 2067.729317] graphics fb1: fb_st7735r frame buffer, 128x160, 40 KiB video memory, 4 KiB DMA buffer memory, fps=20, spi0.0 at 32 MHz

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E. 測試:
     1. Console
          > Map console 1 to framebuffer 1, login screen will show up on the display
         $ con2fbmap 1 1

     2. Image viewer
         $ sudo apt-get -y install fbi
         $ wget http://art110.wikispaces.com/file/view/Mystery-100x100.jpg/30649064/Mystery-100x100.jpg

          $ chmod 755 Mystery-100x100.jpg
          $ fbi -d /dev/fb1 -T 1 -noverbose -a Mystery-100x100.jpg

     3. mplayer
         $ sudo apt-get install -y mplayer
         $ wget http://fredrik.hubbe.net/plugger/test.mpg
         $ chmod 755 test.mpg

          // play with loop infinitely
          sudo SDL_VIDEODRIVER=fbcon SDL_FBDEV=/dev/fb1 mplayer -loop 0 -vo sdl -framedrop test.mpg

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F. 開機時自動啟動播放影片(建議方式)
$ sudo nano .bashrc
....
# auto load fbtft_device:adafruit18 &  play loop video: test.mpg
sudo modprobe fbtft_device name=adafruit18

sudo SDL_VIDEODRIVER=fbcon SDL_FBDEV=/dev/fb1 mplayer -loop 0 -vo sdl -framedrop test.mpg

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G. Shell Script
     檔名: run_nuit_blanche.sh

#!/bin/bash
sudo modprobe fbtft_device name=adafruit18

sudo SDL_VIDEODRIVER=fbcon SDL_FBDEV=/dev/fb1 mplayer -loop 0 -vo sdl -framedrop nuit_blanche.mpg

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H. Framebuffer mirroring
    1. 說明:
        By mirroring /dev/fb0 onto /dev/fb1, we can take advantage of the GPU for
        hardware accelrated video playback.

       fbcp takes a snapshot of /dev/fb0, copies it to /dev/fb1 and waits 25ms before
       repeating.

       Snapshotting takes ~10ms and with a 25ms delay it gives roughly
       1000/(10+25) = 28fps

       CPU usage: ~2%
       Note: Snapshot and /dev/fb1 driver refresh is not syncronized.

    2. Install fbcp:
        $ sudo apt-get install cmake       
        $ git clone https://github.com/tasanakorn/rpi-fbcp
        $ cd rpi-fbcp/
        $ mkdir build
        $ cd build/
        $ cmake ..
        $ make
        $ sudo install fbcp /usr/local/bin/fbcp

    3. Load drivers and fbcp:
        $ sudo nano .bashrc
....

############
# start fbcp
echo "tty = $(tty)"

if [ $(tty) == "/dev/tty1" ]; then

  echo "We have a match."
  cd
 
  # Load fbcp drivers and run fbcp
  sudo modprobe fbtft dma
  sudo modprobe fbtft_device name=adafruit18 
  # rotate=90 speed=48000000 fps=50

  # Start fb copying process in the background
  sleep 3
  fbcp &
  #/usr/local/bin/fbcp &

  # Play video on /dev/fb0, which will also show up on /dev/fb1
  # 720x480
  # --win x1,y1,x2,y2
  sleep 1
  omxplayer -b --loop --win 180,120,540,360 160x128.mp4

  # Stop framebuffer copy
  #killall fbcp 
 
else
  echo "We dont match."
fi

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I. 其他
   1. 檢查沒有接螢幕時的預設視窗大小
       $ /opt/vc/bin/tvservice -s
       state 0x120006 [DVI DMT (4) RGB full 4:3], 720x480 @ 60.00Hz, progressive

   2. 設定預設視窗大小
       $ sudo nano /boot/config.txt
....
# uncomment to force a console size. By default it will be display's size minus
# overscan.
#framebuffer_width=1280
#framebuffer_height=720
#framebuffer_width=720
#framebuffer_height=480
....