After a good bit of Linux kernel hacking on a driver for the ST7735R LCD controller chip, I got them to run as as the Pi's console device.
Video demos of the whole thing in action:
The 1.8" TFT LCD SPI-bus display modules available from Adafruit and SainSmart are functionally equivalent, except that the SainSmart unit can be driven at a much faster SPI bus rate than the Adafruit (32 MHz vs. 4 MHz in my testing). Fabien Royer has shown that this is due to a slow level shifter in the Adafruit unit.
The original st7735fb kernel driver was by Matt Porter, and was enhanced by Lady Ada, Neil Greatorex, and myself. I started with Neil's proposed version of Matt's st7735fb driver, which I extracted from Lady Ada's raspberrypi kernel repo. I applied Neil's version to the current raspberrypi 3.2.27+ kernel, then I made multiple enhancements to the st7735fb driver (and fixed a glitch in the bcm2708 SPI driver). I've since collaborated with Neil to develop further enhancements, and ported the driver to the upcoming 3.6.y Raspberry Pi kernel.
The source for my Raspberry Pi st7735fb kernel is available from my raspberrypi-linux repo.
More technical details and instructions are below. Also note this nice st7735fb driver build tutorial by Mark Williams.
Thanks: Matt, Lady Ada, Neil, Fabien, and Mark for publishing your work; Adafruit and the Rasperry Pi Foundation for all the good stuff you do.
The wiring connecting the Raspberry Pi to the display module is as follows (or use a carrier board as shown below):
|RasPi P1 header||Adafruit 1.8" TFT||SainSmart 1.8" TFT|
|GPIO 11 (SCLK)||SCK||SCL|
|GPIO 10 (MOSI)||MOSI||SDA|
|GPIO 8 (CE0) *||TFT_CS||CS|
|GPIO 24 **||D/C||RS/DC|
|GPIO 25 **||RESET||RES|
$ git clone git://github.com/kamalmostafa/raspberrypi-linux.git $ cd raspberrypi-linux $ git checkout rpi-3.2.27+kamal-st7735fb -- OR -- $ git checkout rpi-3.6.y+kamal-st7735fb
Create your initial build .config file (using this or some other method):
$ make bcmrpi_defconfig # ... or something else to create .configThen customize your .config file, as follows:
$ sed -i /CONFIG_FB_ST7735/d .config $ sed -i /CONFIG_SPI_BCM2708/d .config $ make oldconfigYou will be prompted to select several options about your ST7735 panel configuration. Answer those as shown below, or type '?' for as short description of each option.
BCM2708 SPI controller driver (SPI0) (SPI_BCM2708) [N/m/y/?] (NEW) Y ... ST7735 framebuffer support (FB_ST7735) [N/m/y/?] (NEW) Y ST7735 'red tab' panel type? (FB_ST7735_PANEL_TYPE_RED_TAB) [Y/n/?] (NEW) Y ST7735 panel has reversed RGB? (FB_ST7735_RGB_ORDER_REVERSED) [N/y/?] (NEW) N (or Y if red and blue are reversed) ST7735 framebuffer mapping to GPIO/SPI (FB_ST7735_MAP) [Y/n/m/?] (NEW) Y ST7735 RST gpio pin number (FB_ST7735_MAP_RST_GPIO) [-1] (NEW) 25 ST7735 D/C gpio pin number (FB_ST7735_MAP_DC_GPIO) [-1] (NEW) 24 ST7735 SPI bus number (FB_ST7735_MAP_SPI_BUS_NUM)  (NEW) 0 ST7735 SPI bus chipselect (FB_ST7735_MAP_SPI_BUS_CS)  (NEW) 0 ST7735 SPI bus clock speed (Hz) (FB_ST7735_MAP_SPI_BUS_SPEED)  (NEW) 4000000 (or 32000000 for SainSmart) ST7735 SPI bus mode (0, 1, 2, or 3) (FB_ST7735_MAP_SPI_BUS_MODE)  (NEW) 0
Now "make" and install your kernel as usual. (Unsure about the install procedure? Try Mark's tutorial for more details).
fbcon=map:10 fbcon=rotate:1 fbcon=font:ProFont6x11
Note that con2fbmap also works; it can be used to dynamically remap the console tty's after boot.
$ mplayer -vo fbdev2:/dev/fb1 -x 128 -y 160 -zoom yourmoviefile.mp4
To use fbterm instead of the standard fbcon/getty login session, create the following fbterm-login script and modified /etc/inittab to launch that instead of getty on tty1:
#!/bin/bash # example: fbterm-login fb1 tty1 export FRAMEBUFFER=/dev/$1 exec /usr/bin/fbterm -r 1 -- /bin/login < /dev/$2modify /etc/inittab ...
# 1:2345:respawn:/sbin/getty --noclear 38400 tty1 1:2345:respawn:/sbin/fbterm-login fb1 tty1The rotation and font size of the terminal session can be changed by adjusting the fbterm -r 1 command line switch, or adding e.g. -s 5.
This "Pi TFT Shield" carrier board available from Texy provides a convenient way to mate a 1.8" TFT panel module to the Raspberry Pi:
The board supports multiple different 1.8" panel pinouts including Adafruit and SainSmart, and sports mounting pads for three GPIO buttons. Very nice!