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https://github.com/rm-hull/st7735fb

Schematics and build info for assembling a custom Raspberry Pi kernel with ST7735 TFT-LCD framebuffer drivers
https://github.com/rm-hull/st7735fb

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Schematics and build info for assembling a custom Raspberry Pi kernel with ST7735 TFT-LCD framebuffer drivers

Host: GitHub
URL: https://github.com/rm-hull/st7735fb
Owner: rm-hull
Created: 2013-02-10T19:32:54.000Z (almost 12 years ago)
Default Branch: master
Last Pushed: 2013-05-02T22:11:40.000Z (over 11 years ago)
Last Synced: 2024-10-03T12:17:40.717Z (about 2 months ago)
Language: Python
Homepage:
Size: 11.9 MB
Stars: 29
Watchers: 8
Forks: 5
Open Issues: 2
Metadata Files:
- Readme: README.md

Awesome Lists containing this project

README

        ST7735 FrameBuffer for Raspberry Pi

===================================

The ST7735 is a single-chip controller/driver for 262K-color, graphic type 

TFT-LCD, which can be picked up on eBay relatively cheaply with pin-outs on

a break-out board.

![1.8" 160x128 pixel TFT-LCD](http://www.adafruit.com/adablog/wp-content/uploads/2011/12/window-57.jpg)

Tested working with Rev B 512Mb Rasberry Pi (Raspbian "Wheezy" & latest kernel sources - 3.8.11+). 

A couple of video demos are available here: 

* https://vimeo.com/59438789

* https://vimeo.com/59765667

Further technical details for the LCD screen can be found in the 

[datasheet](https://github.com/rm-hull/st7735fb/blob/master/doc/tech-spec/datasheet.pdf?raw=true) [PDF]. Other documentation

can also be found in [docs/tech-spec](https://github.com/rm-hull/st7735fb/tree/master/doc/tech-spec).

Building and installing the frame buffer driver

-----------------------------------------------

1. On the Raspberry Pi, enable SPI: edit `/etc/modprobe.d/raspi-blacklist.conf`

   to comment out blacklisting of _spi_bcm2708_.

2. Ensure that the latest firmware has been applied to the Raspberry Pi. Use the updater from

   https://github.com/Hexxeh/rpi-update to perform the update (use the BRANCH=next prefix). 

   After rebooting, confirm the kernel version as follows (digits xx and yyy dont matter too much):

    ```

    $ uname -a

    Linux raspberrypi 3.8.xx+ #yyy PREEMPT ...

    ```

3. Ensure the gcc build tools are installed on a host PC (it is much

   quicker to cross-compile on an x86 linux machine than build the 

   kernel on the RPi): 

    ```

    $ sudo apt-get install make build-essential ncurses-dev git-core

    ```

     

4. Download the kernel sources with the ST7735 drivers:

    ```

    $ mkdir ~/RPi

    $ cd ~/RPi

    $ git clone https://github.com/rm-hull/raspberrypi-linux.git

    $ git checkout rpi-3.8.y+rmh-st7735fb

    ```

5. Download the cross-compiler tools:

    ```

    $ cd ~/RPi

    $ git clone git://github.com/raspberrypi/tools.git

    ```

6. Follow the instructions for building a cross-compiled kernel [here](http://elinux.org/RPi_Kernel_Compilation).

   Note that when the guide refers to `.config`, this is provided as `etc/config.gz` in git.

   Let's assume that the tools are installed in `~/RPi/tools`, and the kernel source is `~/RPi/raspberrypi-linux`. 

   Briefly the compile steps are: 

    ```

    $ cd ~/RPi

    $ export CCPREFIX=~/RPi/tools/arm-bcm2708/arm-bcm2708hardfp-linux-gnueabi/bin/arm-linux-gnueabi-

    $ export MODULES_TEMP=~/RPi/modules

    $ wget https://github.com/rm-hull/st7735fb/raw/master/etc/config.gz

    $ cd raspberrypi-linux

    $ make mrproper

    $ zcat config.gz > raspberrypi-linux/.config

    $ make ARCH=arm CROSS_COMPILE=${CCPREFIX} oldconfig

    $ make ARCH=arm CROSS_COMPILE=${CCPREFIX} -j 6

    $ make ARCH=arm CROSS_COMPILE=${CCPREFIX} INSTALL_MOD_PATH=${MODULES_TEMP} modules_install

    ```

Once compiled, scp the `arch/arm/boot/zImage` over the `/boot/kernel.img` on the Raspberry Pi (make a backup first). 

Next copy the `~/RPi/modules/lib/modules/3.8.11+` directory to `/lib/modules/3.8.11+` on the device (again move the

existing directory out of the way first).

On rebooting, you should get a second frame buffer at `/dev/fb1`, and the screen should present a nice gradient pattern. 

Break-out board pin-outs

------------------------

There appear to be a large number of break-out boards available for this device; this is the one 

I have, with an additional SD card slot:

| TFT Pin | Name | Remarks | RPi Pin | RPi Function | Wire color |

|--------:|:-----|:--------|--------:|--------------|------------|

| 1 | GND | Ground | 6 | GND | Black |

| 2 | VCC | Power | 1 | 3V3 | Red |

| 3 | NC | | | | |

| 4 | NC | | | | |

| 5 | NC | | | | |

| 6 | RESET | Set low to reset | 18 | GPIO 24 | Blue* |

| 7 | A0 | Data/command select (aka DC or 'register select') | 16 | GPIO 23 | Grey* |

| 8 | SDA | SPI data | 19 | GPIO 10 (MOSI) | Orange |

| 9 | SCK | SPI clock | 23 | GPIO 11 (SPI CLK) | Brown |

| 10 | CS | SPI chip select - set low | 24 | GPIO 8 (SPI CS0) | Green |

| 11 | SD-SCK | SD serial clock | | ||

| 12 | SD-MISO | SD master in, slave out | | ||

| 13 | SD-MOSI | SD master out, slave in | | ||

| 14 | SD-CS | SD chip select | | ||

| 15 | LED+ | Backlight control 3V3 - 3V7, already fitted with 10K resistor? | 1 | 3V3 | Red |

| 16 | LED- | Backlight ground | 6 | GND | Black |

*-not shown on stripboard layout below - direct track connection.

Stripboard Layout

-----------------

With 4 push-buttons, resistor values 10K.

![Stripboard Layout](https://raw.github.com/rm-hull/st7735fb/master/doc/schematic_bb.png)

Buttons (from left to right) are wired onto BCM pins as follows:

* GPIO 22

* GPIO 25 

* GPIO 17

* GPIO 14 (TxD)

Also: Dallas Semiconductors DS18B20 digital thermometer, wired onto GPIO 4, with 4.7K pull-up resistor. See 

separate usage note [here](https://github.com/rm-hull/st7735fb/blob/master/DS18S20.md).

Testing

-------

### mplayer

_scale_ is used because the movie is larger than most small displays. -3 means keep aspect ratio and calculate height.

    $ sudo mplayer -nolirc -vo fbdev2:/dev/fb1 -vf scale=156:-3,rotate=2 examples/video/bird-is-the-word.mp4 

### Image viewer

    $ FRAMEBUFFER=/dev/fb1 fim examples/images/tux-small.png

Using the LCD as a console device

---------------------------------

To use the display as a console, the kernel must be re-compiled with the BCM SPI & ST7735 drivers 'baked in' 

rather than as separate modules (the config settings above do this); add this to the end of the line in 

`/boot/cmdline.txt`

    fbcon=map:10 fbcon=rotate:3 fbcon=font:MINI4x6

See [fbcon doc](http://www.mjmwired.net/kernel/Documentation/fb/fbcon.txt#72) for more info.

And the finished article:

![Built stripboard](https://github.com/rm-hull/st7735fb/blob/master/doc/images/IMG_2774.JPG?raw=true)

Examples

--------

The framebuffer is owned by root, so first:

    $ sudo -s

    $ export FRAMEBUFFER=/dev/fb1

To demo the maze generator:

    $ python maze.py

Copper bar animation:

    $ python copper_bar.py

Snake game (needs Wii Remote and bluetooth enabled):

    $ python snake.py

TODO

----

* Extended documentation

* Improve build instructions

* Example code (SDL / Python)

References

----------

* http://elinux.org/Rpi_Low-level_peripherals#General_Purpose_Input.2FOutput_.28GPIO.29

* http://www.sitronix.com.tw/sitronix/product.nsf/Doc/ST7735?OpenDocument

* http://learn.adafruit.com/1-8-tft-display

* http://www.raspberrypi.org/phpBB3/viewtopic.php?t=28696&p=262909

* http://elinux.org/images/1/19/Passing_Time_With_SPI_Framebuffer_Driver.pdf

* http://www.flickr.com/photos/ngreatorex/7672743302/

* https://github.com/notro/fbtft

* http://www.areinhardt.de/news/raspberry-pi-tft-display/

* http://www.whence.com/rpi/

* http://fritzing.org

* http://harizanov.com/product/1-8-tft-display-for-raspberry-pi/